Oliver Lansley is modest about his portrayal of the iconic comedian and DJ Kenny Everett in the BBC Four biopic.

"I wouldn't say I was a natural impressionist," he insists, despite mastering Kenny Everett's mad array of characters, not to mention his ever-changing accent.

"For me, the key to getting those characters right was firstly to understand what it is Kenny sees in the character that he wants to grab onto. He has a real passion for language which, as a writer, is something I share. You can hear the words in each character he loves to say in those voices. That was a real way in for me, it helped me more than thinking about doing an American accent or a punk... What did Ev find that he loved and enjoyed? I found the key to him through his characters; they're incredible but they're still always him. A perfect example is Cupid Stunt when he dresses as this wonderfully glamorous woman but has still got the beard. For me that sums up the characters; underneath the make up and facade you can always see Kenny Everett.

"The other real moment that helped was when I was preparing for the audition. I was trying to ape and mimic what I'd been watching on the internet and there was a moment when I stopped trying to do what he did and started to use the characters to make my friends and girlfriend laugh and suddenly it came alive. For me it was about finding what he found in the characters, rather than simply copying him.

"What was also hard was finding the version of him I was going to play; every interview I listened to he sounded different. You could listen to hours of him talking and you wouldn't know he was from Liverpool and then listen to some where he had a thick Scouse accent. I think it depended on how comfortable he was. I had to find the right balance because he had a great mastery of language and used all the tools at his disposal."

Oliver recalls how he actually landed this dream role.

"Kenny was definitely looking down on me when I got the job I think as it was very serendipitous. I'm a writer as well and I happened to have a meeting with Mammoth to discuss writing something for them. We got to discussing other projects and they mentioned the Kenny biopic they were working on - my eyes lit up and immediately I said what an exciting project it would be, and I actually started to suggest other actors for it! The thought of myself honestly didn't cross my mind as I assumed they'd be looking for a big name. Anyway, unbeknownst to me they'd been searching far and wide for their Kenny and it was fairly late in the day. I happened to have a beard at the time as I'd just got back from holiday and so bore a passing resemblance to Ev, and they knew I was an actor and so out of the blue I got a phone call the next day asking me to audition.

"So the day after the meeting I got the call and went in to meet the casting director and to put myself on tape. Then I got a phonecall asking if I could come in and meet the director and producers. I turned up on the Monday, the last day of auditions, the last person of the day. Terrifying! I'd never worked so hard at an audition in my life, I even brought my own wig."

Oliver admits he mostly remembers Kenny Everett because "my dad looked exactly like him when I was little".

He explains: "I was a bit young to be watching his TV show but he is so iconic, he stuck in my head, and as soon as I heard about the biopic I knew his would be an incredible story to tell.

"When I started watching footage for the audition I began to realise how groundbreaking he was in the medium of broadcast; what he did for radio is extraordinary. And then he did the same for TV.

"Watching his show now, it still holds up. It's a cliche but he really was ahead of his time. He had a real desire to push things forward.

"We talk about the golden age of comedy and classic comedy but Kenny Everett is more like this generation. He is rebellious without ever attempting to rebel. He is so original, so anarchic and chaotic and full of this electric energy."

And Oliver needed plenty of that energy to tackle the costumes changes on Best Possible Taste: The Kenny Everett Story.

"The last two days of filming were crazy. I was Verity Treacle, Angry of Mayfair, Sid Snot, all three Bee Gees, Quentin Pose, Marcel Wave... it was hilarious, there would be someone taking off my wig and a person pulling off each leg of my tights because each costume change had to be so quick. I was like a kid in a dressing up box.

"We filmed one scene at Camber Sands so there was me wandering along a beach in high heels and fishnets, all manner of different undergarments, a beard and a pair of giant fake boobs. That was a first, but then I had a lot of firsts on this job.

"My favourite character was probably Cupid Stunt because she's such fun to play, but the giant hands of Brother Lee Love were tremendous. Everyone on the crew had their photo taken wearing them and I desperately wanted to take them home!"

Oliver admits: "I've never played a real person before so it has been an interesting challenge for me. All the other people in the script are still around and spending time with them made me realise this is about a real person who means a hell of a lot to people and that elevates it beyond an acting job. I feel a responsibility, which does add pressure, but on the flip side it focuses you and stops you from being a self-indulgent actor. For me, the most important thing was to get it right for everyone who had spent so much time on the project.

"When I was researching the role I asked everyone involved, what is the one thing I should keep hold of, and they all said Ev's childlike quality. He was a life force who affected everyone he was around but he had a sort of innocence to him. He never thought he was going to get hurt and you can see that he always got into trouble because he never quite thought it would end the way it did. He was incredibly naughty, always pushing the boundaries.

"And he had such a love for the BBC, right from when he was young and listened to the World Service. He had a passion for it and was frustrated it wasn't as good as he wanted it to be. The way he always pushed them came from him wanting the BBC to be more groundbreaking - it was a paternal relationship and he was a wayward child trying to please them which is why it feels so right doing this film for the Beeb now."

Talking about his co-star Katherine Kelly, who plays Kenny Everett's wife, Lee Middleton, Oliver says: "Kate is unique; there are not many actors who could walk out of five years of Coronation Street straight into the National Theatre and then do this in between.

"The thing that immediately struck me was that there is a real openness about Kate, a real sense of truth. She is one of those actors who make you better working with her. Kate is so generous and lovely to work with, a real joy, which is so important as we had to trace Lee and Kenny's relationship. There is a lot we have to portray and it's important to make sure people see it wasn't a sham but that it was born out of genuine affection. There is only so much you can script so what we have to capture is their chemistry and closeness. For both of us it's something we felt passionate about trying to get right, that sense of genuine intimacy and understanding."

Oliver continues: "What I love about the script is that it has real warmth to it. It touches on harder times in his life but it is very joyous and celebratory of Ev and his work and at the centre is this unique and wonderful love story between him and Lee. It's about a connection between two people; such a bittersweet story. And it was a similar love story with his work, the other constant in his life, and the love-hate relationship he had with himself. Kenny was such a bundle of contradictions, and this is about him trying to find acceptance of himself.

"Writer Tim Whitnall did an extraordinary job with the script. There is so much in it and to be able to weave that into a cohesive story is unbelievable. It blisters with affection and knowledge of its subject. Fundamentally he cares about Ev and that's what made it easier for me: it was all there and I never had to question it."

Oliver Lansley's writing credits include FM for ITV2 and Whites for BBC Two. Last year he wrote and directed The Curious Incident Of The Dog In The Daytime for Sky's Little Cracker season, starring Alan Davies.