Few TV shows have been as successful as Friends. The US sitcom made its stars household names the world all over. So, getting recognised by the British public is something that David Schwimmer - who played Ross in the series - has come to expect.

"I have learned how to be invisible at times, and then there are times that are more challenging," admits the 59-year-old actor and director, who was born in New York and raised in LA.

"But everyone's super nice; luckily the show was a real success here, so for the most part, it's just a lot of love."

He never actually says the word 'Friends', but it's pretty obvious that's the show he's referring to.

It's summer 2019, and we're chatting on the set of his latest project, Sky One comedy, Intelligence.

The backdrop is the Government Communications Headquarters - an intelligence and security organisation commonly known as GCHQ - where they tackle international and domestic Cyber Crime from a desktop.

And Schwimmer - also known for his role in drama, The People v OJ Simpson: American Crime Story - plays maverick NSA agent Jerry Bernstein, who moves from the US to join the team.

Starring alongside him, as inept and tactless computer analyst Joseph Harries, is Nick Mohammed, 39, who also created and wrote the show.

"The premise is that it's quite a British institution, and the shake-up that happens when David's character comes from the NSA - the culture clash and difference in style and approach," explains the Leeds-born comedian, who voiced Piglet in the live-action film Christopher Robin film.

This is not a parody show, he points out. GCHQ is a real institution, that deals with serious issues (there's a whole branch of the service that tackles child pornography and sex trafficking of minors).

And something he wanted to make sure he got right was how he handled the subject matter; he wanted to do it "properly and tastefully".

"We felt it would be strange if we weren't referencing occasionally real-life atrocities - but never to poke fun.

"I think we just wanted to make it feel as real as possible, and that we might have to deal with the after-effects of very horrible things. I mean, we never dwell on it..."

He elaborates thoughtfully: "Because their chief thing is fighting Cyber Crime and combating computer viruses and database breaches, I guess there's a slight detachment from an event like the Manchester bombing. It's not to say that there's places that we wouldn't go... you know, we reference 9/11."

"Yeah, there are a couple of jokes in there that are right on the edge, like, 'Can we make this joke?'" Schwimmer chimes in.

"But our feeling is, 'Let's shoot it and we'll decide in the edit'. 'We'll do this way, and then we'll do a safer version'."

Jerry is very patriotic, and hugely critical of any country outside the US, as well as being suspicious of all other peoples and languages.

Schwimmer notes he's finding him "quite a cathartic character to play at the moment".

"All the things I might be upset about that are happening in my country and in some quarters, I can play - and try to embody the type of person that is incredibly racist and sexist and misogynist and homophobic, but play it in a way that I think we've found is quite funny and naive, and comes from a certain place. He's ignorant and insecure."

"It's a fine line to make racism funny, or misogyny funny," he adds. "I think we're doing it, because it's coming from a certain character, who people can see like, 'Wow, that dude's got problems'."

You can expect some broad physical comedy in the series (something which Schwimmer says really appealed to him).

One example of this is a scene in episode two where all the employees have to re-do their aptitude test.

"It involves a lie detector test, physical exercises and mental thinking," explains Mohammed. "We effectively did it for real, and we were all improvising, and everyone was laughing all the way through it."

While you might think improvisation would be nerve racking, the writer assures "it's easier than learning lines!"

"We always make sure we have what's on script first, so we know we are telling the right story, because occasionally the improvisation, by its nature, can wander and meander a little bit.

"But you can just occasionally get some very nice, very fresh, electric moments - usually on the cusp of it all falling apart."

The friends would often discuss ideas for the characters whilst on set.

Asked if there was ever disagreements when it came to certain scenes, Schwimmer says: "I would never use the word disagreement. It's just a really healthy creative challenge of each other."

Mohammed recalls how, early on in the writing process, he would often write "quite silly sequences", and have to be reminded that it needs to feel like he's writing about a real place.

"I would maybe push it a bit too far. But I think that's really healthy, in a way, because you need to be edited.

"It's been effortlessly collaborative, this show. Obviously I don't have nearly as much experience as Schwimmer, but I hope this is the case for lots of shows..."

"It's not..." Schwimmer quickly retorts.

The star has certainly had a varied career, and this isn't the first time he has worked on British soil either. He spent five months here directing the 2007 film Run Fat Boy Run, plus he did a stint on the West End back in 2005.

"The only difference now is I have an eight-year-old daughter who's here, trying to carve out time to see her and spend time with her.

"Nick's got two boys, so we actually had a Sunday at Kew Gardens last Sunday with the kids. That was fun."

"I like London a lot," he continues, smiling.

"Everything just feels really comfortable; the crews are great, the vibe on set is really warm and friendly. And I think we were both surprised just how easy everything fell into place with the cast.

"There's no ego anywhere on set - it really is 'the best idea wins', and that's really the dream way to work."

Intelligence launches on Sky One on Friday, February 21