FOOTBALL might still be 'soccer', lifts are 'elevators' and towns are 'neighbourhoods', but despite the odd difference in vocabulary, Hollywood actor Jeremy Piven is right at home in Britain, where he spends half the year filming ITV's Mr Selfridge.

"I've loved being in the UK," says the 49-year-old, who is ever the gent in a pale suit, paisley shirt and pocket square.

"My only regret is that I haven't had more time here. Shooting a one hour costume drama takes a lot of time."

Indeed, if it wasn't for the fact that Piven is currently in the middle of a global publicity tour to promote the Entourage film, he'd be in North London, "grinding it out in a converted carpet factory shooting my show [Mr Selfridge]".

But it's his other show - or its movie version, rather - that brings him here today.

A world apart from the smooth charm of Mr Selfridge, hit US comedy series Entourage made Piven a star across the pond, for his performance as easily riled super agent Ari Gold.

Running for eight series, it followed the exploits of upcoming and upstart movie actor Vince Chase and his inner circle of mates, who he enlists to drive, manage and support him as his star rises.

In the movie, relentless, ruthless and potty-mouthed as ever, Ari's first decision as the head of a mega film studio is to hire Vince to front a major new film, which the actor, in all his swagger, decides he also wants to direct.

"Vince has promised Ari he wouldn't go over budget, and that's exactly what he does," explains Piven, who has a Golden Globe and three Emmy awards to his name thanks to the Entourage series.

"It makes Ari crazy because he's already stuck his neck out for these guys. And it means everything to him that Vince's movie turns out good, because their entire future is in that movie. If they don't deliver, they're all screwed. The stakes couldn't be higher, and that's not exactly great for Ari's stress level."

After a four-year break from the character's foul-mouthed monologues, being able to let rip again is something Piven relished. Indeed, over the years, the team has learned to stand back when the "passionate" actor starts improvising, mid Ari rant.

As production designer Chase Harlan explains: "We've had to have a couple of backup TVs or computers for Ari's desk, because you never know when, as Ari, Piven's going to, well, throw it off the desk."

Away from set, Piven is a poised presence, neatly folding his hands in his lap and calmly chatting.

And yet beneath the glasses, there is a glint of Ari in his shrewd consideration of questions, though he insists he is nothing like the Hollywood power player.

"Harry Selfridge is the antithesis of Ari, and he's actually more like me, in a way," he explains, smoothing his well-kept beard. "Going back to Ari was a lot of fun."

The son of two actors, Piven grew up in the Northern Chicago suburb of Evanston and, after graduating from drama school, soon started landing TV roles, including a long stint in The Larry Sanders Show from 1992.

Given his family background and long showbiz career, it's no wonder he's wise to the Ari types in Hollywood.

"Hollywood is a very strange place to navigate, that's for sure," he says. "There are so many Ari Golds out there. And the problem is that the way we portrayed Ari, he was brutally honest, but you at least knew where he was coming from.

"But a lot of times in Hollywood, someone will say they love you and the reality is quite different, so it's very confusing."

Piven insists that rather than taking all hyperbolic declarations of love to heart, he is able to keep a distance from Hollywood hype, even admitting he "steals" and draws from his experience of it to feed the monster that is Ari.

"I'm so different to the Ari Golds of the world," he adds with a smile. "Dealing with them used to be painful and now I find it entertaining."

These days, splitting his time between Los Angeles and London, his life is the UK is, nevertheless, still pretty starry.

There's his attendances at Prince William and Harry's annual polo contest in Ascot ("They're very present, humble and sweet"), the trips to Wimbledon with Jonathan Ross and Jimmy Carr for company, and the glittering honour of being Rolling Stones guitarist Ronnie Wood's favourite TV character (Mr Selfridge).

Aside from his enviable social calendar and connections, theatre-lover Piven has also taken full advantage of his extended stays in Blighty.

"It's fun to immerse yourself in British culture," says the actor, whose film credits also include Rush Hour 2, Serendipity and Black Hawk Down.

"I've seen some of the best theatre I've ever seen in my life here. It's such a treat to go to the Young Vic and see Mark Strong in A View From The Bridge. He's such a genius and a friend. And then going to The National and seeing the classics... It's a very fun and inspiring place."

Inspiring enough that it's changed his approach to his career...

"I've noticed that actors and creative people in the UK are in fear of repeating themselves," explains Piven, who also plays drums in a band called the Bad Decisions.

"You see them not wanting to do a series for too long and wanting to work on their range, and it's so beautiful.

"I think the experience in England, playing opposite all these brilliant actors and working with all the folks, has made me better at whatever it is I do."

Entourage is released in cinemas on Friday, June 19