I have touched Billy Connolly's coattails with the best of them so I know what it is like to have a brush with stardom. This brief encounter with the Big Yin's coat of many colours happened the night before the opening his new exhibition, Born on a Rainy Day, opened at Glasgow's Castle Fine Art gallery.

Connolly has been signed to the chain of fine art stores since 2012. There are 40 shops throughout the UK, specialising in original and limited edition fine art prints and sculptures. As well as Connolly, its roster of artists includes the photographer, Eve Arnold, and singer songwriter, Bob Dylan. The opening of the Glasgow leg of his show on March 12 was greeted with a media scrum, the like of which most artists I know would kill for but rarely receive.

The night before, I was out for a birthday meal with my family in the Finnieston Strip's new go-to restaurant, Gloriosa, when the Big Yin walked in. There was a slight lull in conversation among the assembled diners, but it doesn't do to make a fuss in the west end when a living Glasgow leg-end is in the room, so we all pretended he wasn't there, while sneaking a glance now and then.

As we left, my 18-year-old son had to reach up and remove Connolly's coat from its peg so he could retrieve mine. We exchanged a knowing look. Such is the allure of celebrity that touching a star's coat gives you a wee thrill.

In a sense, it is this frisson of "owning" a wee piece of Connolly in the shape of one of his art works – be that an original drawing or a signed limited edition print – which is driving the boom in sales of his work at Castle Fine Art's swish and spacious gallery opposite the Gallery of Modern Art in Queen Street. And boom it is.

When I called in earlier this week, all around, high street stores were closing down thanks to Covid 19. Undaunted, potential buyers were browsing the Connolly artworks; a mix of original drawings in felt tipped pen and limited edition (in sets of 295) giclee prints of these drawings. All 22 original drawings had been sold while red dots were peppered throughout the store beside the digital prints.

Although during his early troubadour days in stand-up, he hung out with the Glasgow School of Art crowd and was friends with the likes of John Byrne and George Wyllie, Connolly has said that he stumbled into making art one day in 2007 while on tour in Montreal. It was a rainy day; the day which gave the exhibition its title. Bored watching television, he found an art shop opposite his hotel, bought a sketch book and some felt-tip pens.

He started doodling in his room and didn't stop. If it had been anyone else, the drawings would probably have been gifted to friends and family on high days and holidays, but Connolly is a performer to his Banana Boot-straps. He may have given up stand-up but his art still puts him on a very public platform. Our fascination with the Big Yin transcends genres be it music, comedy or art.

There is of course, a history of doodling in art. The Swiss-born artist Paul Klee (1879-1940) once said: "Drawing is the art of taking a line for a walk," and it's a motif which crops up regularly in 20th century art. The Scottish artist, Alan Davie, doodled almost until the day he died, relishing the freedom it brought to his painting.

On the day I visited Born on a Rainy Day, it was busy. Couples were taking photos of one another in front of Connolly's work while a gallery assistant urged them to put a small deposit on a print if they were thinking about buying in order to secure it. Signed and numbered limited edition digital prints of the likes of First Position, a typically surreal Connolly take on a ballet position, complete with tartan legs which look like they have been welded together, were selling out fast, she said. This despite the £950 price tag.

Likewise, the print of a Scotty Poser drawing (£995), a quirky rainbow-hued dog with a clean black line and a body consisting entirely of a riot of neat coloured lines, had sold out on the opening night.

All 22 original drawings, including a self-portrait pencil sketch called Portrait in Self-Doubt, were "pre-sold" before the opening of the exhibition. Also for this exhibition, a fancily-titled "time-limited boutique edition" of a signed print of a Connolly drawing called Glasgow, depicting a tree adorned by a fish, a bell and a bird has been produced. Any clients of the gallery who live in Glasgow had the chance to buy it this signed print for £1250. The deadline was Thursday past.

I feel bad writing this, but I wonder if Connolly needs the cash or if the gallery has simply hit on a money machine because, while his drawings and the prints of his drawings are perfectly pleasant to look at and make you smile, I know literally hundreds of amazing artists who sell original artwork for a fraction this price. The Glasgow drawing is not his finest.

Some of the drawings are sweet and even suffering from Parkinson's Disease as he does, Connolly is still a creative buzzball of surreal energy. There is a child-like honesty to his work, laced in with the trademark surreal humour. His titles are especially good. Some, like New Life and The 60s, are a complicated and tender mix of multi-coloured order and chaos within a clean line, while others, such as Treasure Island seem to be a weird mix of psychedelic blobs in a sea of lines.

For this – the fifth edition of his Born on a Rainy Day series – there is also a brand new limited edition stainless steel sculpture called And on Monday, God Made the World. Based on Connolly's drawing of the same name, 195 versions of this work have been produced with an eye-watering price tag of £6950. I was told they are almost all gone so if you are looking for one for the house, I fear you’re on to plums.

It's a pleasant-to-look-at shiny thing, depicting what could be the welder Connolly once was in the long-gone Stephens of Linthouse shipyard, complete with angels' wings and welding mask leaning over a silvery globe. But would I buy it? Well, no. I don't have that kind of money for a kick-off, but it also feels to me at any rate that the connection to Connolly has been lost along the corporate chain. People are probably buying with an eye on an investment but I’m not sure the reproductions at any rate fall into the investment category. The drawings are a different kettle of fish.

The exhibition is beautifully presented and on the wall there's a quote from Connolly writ large. It reads: “My art bears no relation to comedy or music. It is pure and unjudged and I am creating for myself. It is personal and private, whereas with a film, comedy show or music you expect people to be critiquing, watching, assessing. Art is different – it liberates you.”

Personally, I find this confusing because art is not different. People do critique, watch and assess in the art world. Constantly. It’s grand to see the Big Yin liberated by his art, but when it comes to selling art, the sheen of celebrity, can take an artist to another level. And that, as they say my friends, is the business that is show.

Born on a Rainy Day, Castle Fine Art, 96 Queen Street, Glasgow, G1 3DN, 0141 221 6867, https://www.castlefineart.com/galleries/glasgow. Until April 22, 2020. Open daily.

Critic's Choice

Glasgow has a rich and varied reputation as a city-wide plinth for public art and a new art trail around the centre of Glasgow is the very ticket for anyone looking to avoid crowded spaces in these testing times. From this coming Thursday, look out for information around Glasgow and online about a brand new Contemporary Art Trail for the city centre, showcasing the many diverse and significant pieces of work that can be found there.

Among the 14 pieces of contemporary art on the trail are; Douglas Gordon’s Empire installation (1997), The Clyde Clock (George Wyllie, 1999, Killermont Street); and Tympanum (Niki de Saint Phalle, 1996, Gallery of Modern Art).

The remaining 11 pieces will be revealed on Thursday. The location of these artworks ranges from Rose Street and Renfrew Street down to Nelson Mandela Place and the Broomielaw, and over to Hutcheson Street and Rottenrow.

Glasgow’s City Centre Contemporary Art Trail is part of the Glasgow City Council's City Centre Strategy and aims to give residents and visitors an opportunity to enjoy some of the contemporary art than can be seen from the streets of the city centre. By shining light on the public art around the city, the trail also underlines the notable cultural role that Glasgow has played, and continues to play, in Scotland, the UK and Europe.

The trail feeds into the High Street Area Strategy, which includes key objectives such as celebrating and promoting the unique local offer; enhancing the look and feel of the area; and increasing footfall to and throughout the High Street and surrounding district. Which can only be a good thing.

A guide booklet for the trail will be available from various museums and cultural venues in the city centre.

https://www.citycentrecontemporaryarttrail.co.uk/

Don't Miss

Prior to the 1960’s, women artists had little opportunity to show their work other than in annual mixed exhibitions, but in 1969, the estimable Compass Gallery was founded to promote the work of contemporary artists, giving many women their first opportunity to have solo exhibitions. Often their varied, sometimes life-challenging life experiences and their strong emotional thoughts enrich their images.

This exhibition presents a small selection of work by stellar talents such as Lys Hansen, Marie Barbour, Heather Nevay and Helen Wilson, all of whom have exhibited with Compass over the years.

21st Century Women, Backdoor Gallery, Dalmuir Library, 3 Lennox Place, Dalmuir G81 4HR, 01389 772011, https://www.west-dunbarton.gov.uk/leisure-parks-events/museums-and-galleries/exhibitions/backdoor-gallery-exhibitions/ Until April 20. Open daily apart from Sunday (see website for opening times). Free