If you are going to have any chance of replicating life, you need to live it.
I also never forgot something Johnny Depp said to me, which Marlon Brando said to him, 'You only have so many faces in your pocket.' I really admire artists who take the time to recharge their batteries and not continually call on it.
"I started out training with the builder as a labourer two years ago and now I'm doing it all myself," he says.
"It's like glorified DIY – I'm renovating it all myself."He feels at home rehearsing the Potter play in the tiny Arcola Theatre.
"The description that Potter gives is somebody who is or imagines himself to be a demon," says Friend – who seems far more of a nature boy than the Devil in real life.
This is the actor's first stage outing since his well-received West End debut at the Garrick Theatre in 2010, playing a closeted film star in Douglas Carter Beane's comedy The Little Dog Laughed.
I think you can spot tired and jaded artists quite quickly."Brimstone and Treacle was written for television and banned by the BBC in 1976 for its provocative content, before Potter adapted it for the stage.
"My character also encourages the dad to admit to his incredible racism, bigotry, Right-wing leanings and pushes him into a place where hatred is celebrated."Friend, a relative new comer to the theatre, has done far more films.From his true story a real-life charity was formed called To Write Love on Her Arms, which has a big following of depressed American teenagers," says Friend.In order to research the role Friend got himself locked up in solitary confinement in a prison in Florida and attended NA and AA recovery meetings all over London."It entails physical and sexual abuse, neglect and a certain amount of religious indoctrination." He is also a con man so Friend has been watching films about con men – Six Degrees of Separation, The Talented Mr Ripley and House of Games. It's about imagining you are somebody else," says Friend."That is as far as I can get in terms of a mission statement."Performing the play in an intimate theatre space such as the Arcola, which is the size of a front room, "is about implicating and involving the audience in a horrific set of circumstances", says the actor."The other actress who isn't in the rape scene walked out today."At Christmas his tin roof flew off so I went up there to help him put it back on in a blizzard," says Friend."I've never thought it was a good idea to act back-to-back.It's like a less funny version of Rhys Ifans in Notting Hill, and not Welsh," says Friend. They couldn't afford a set nor somewhere for me to live.I'd come out of the shower in my towel, and there would be the cameraman in my kitchen, making coffee.Despite a string of films in which he has starred with Johnny Depp (The Libertine, 2004) Michelle Pfeiffer (Chéri, 2009), Emily Blunt (The Young Victoria, 2009), Friend craves quiet, nature and DIY.He is particularly excited about building his own house in east London at the moment.