Comedy star Jack Whitehall is turning his hand to drama, in the BBC’s adaptation of Decline And Fall. He talks to Kate Whiting about the pressure to please Evelyn Waugh fans

In those familiar plummy tones we've all come to know and love, Jack Whitehall declares: "There's rarely something I do where I keep my clothes on!" The stand-up comic and star of Fresh Meat and Bad Education is discussing his first-ever period role, in the BBC adaptation of Evelyn Waugh's 1920s satire Decline And Fall - and admits he was a little disappointed he had to strip.

"My heart sank when I saw that. I was like, 'Period comedy drama - finally this might be the one where I keep my trousers on, and then lo and behold, first scene, they're down! One day, I'll do something where I'm dressed for the whole thing - unlikely though."

Whitehall, 28, plays Paul Pennyfeather, who is 'sent down' from Scone College, Oxford, where he's studying to join the church, for 'indecent behaviour'. What really happens is that members of the notorious Bollinger Club (Waugh's satirical take on the infamous Bullingdon Club - think David Cameron and Boris Johnson), strip him starkers in the college quad.

An orphan, with limited resources, Paul has little choice but to take the first job he can get - as a live-in master at a poorly performing public school in a Welsh castle. He soon makes friends with fellow masters - and oddballs - Grimes (Douglas Hodge) and Prendergast (Vincent Franklin). And so the stage is set for this darkly comic three-parter, which will see Paul eventually land in jail.

"When the script arrived in front of me, I was so excited, because I knew the book as well. It was my father's favourite book and he gave it to me to read when I was teenager," says Whitehall. "The wickedness of it really appealed to my sensibilities. I thought [screenwriter] James' [Wood] adaptation was amazing, it was funny and dramatic and sometimes poignant and sad - it had everything, and it felt like a real challenge to be part of this, so I was champing at the bit to do it."

He's well aware Decline And Fall is also a lot of other people's "desert island book", so he felt an added pressure to do them (and his dad) proud as the hapless Pennyfeather.

"You feel a duty," says Whitehall. "There was a lot of stress in the process of it. It was fun while we were on set, but you are worried constantly that you haven't got it right, and you want to make sure all the fans of the book are happy."

An added bonus was the fact he got to work with master of period drama David Suchet, best known for bringing Agatha Christie's Belgian detective Poirot to life on screen, who plays headmaster Dr Fagan. But it wasn't their first ever encounter - in fact, Suchet and Whitehall go way back.

"One of my first work-experience jobs, I was David's runner in the West End when he did Man And Boy [in 2005]. He was so nice! I've admired him and looked up to him ever since then, so the idea of working with him was a pipe dream," Whitehall explains. "I spent more time corpsing in scenes than I've ever done, when I was watching David and Vincent and Douglas. That was the hardest bit for me, trying to control myself."

He also had a hand in enticing Desperate Housewives' Eva Longoria to play the role of Margot Beste-Chetwynde, the mother of one of Pennyfeather's pupils, with whom he has a relationship. She and Whitehall share the same agent, who "managed get my text in front of her", he says. "She was amazing, very down-to-earth and generous as a performer," gushes Whitehall. "I was a Desperate Housewives fan, so I had to check myself quite a lot from telling her how much I enjoyed her as Gabrielle Solis. Also her husband was on set most of the time. He is literally the coolest and sexiest man I've ever seen, so I spent most of my time when I was wooing her, looking at him and feeling totally emasculated, which was probably quite good for the character!"

Whitehall, who is dating Humans star Gemma Chan, was born into a showbiz family - his mum, Hilary Gish, is an actress and his dad Michael's a producer, best known for co-hosting the talkshow Backchat with his son. The comedian went to school in West London with Twilight star Robert Pattinson and, aged 11, unsuccessfully auditioned to play Harry Potter. After two terms studying History of Art at Manchester University, he dropped out to focus on stand-up and acting.

He's now busier than ever. Just days after completing his biggest live tour to date, and promoting Decline And Fall, he jetted off to Thailand to film a new show for Netflix with his dad, Jack Whitehall: Travels With My Father.

Assuming he pleases the Evelyn Waugh fans with his version of Paul Pennyfeather, it's hard not to imagine we'll be seeing him in more period dramas to come. Whitehall would love that.

"There's a scene in episode three, where they fake my death with a drunk surgeon and it's all orchestrated by Fagan," he reveals. "It was like choreography, like a little play and I was so excited, it was like, 'Oh my God, I think I might be doing proper acting!'"

  • Decline And Fall is on BBC One from Friday, March 31