There's something rather endearing about Rupert Graves. Despite our meeting being scheduled for early evening, Graves appears to have just got out of bed. Dark hair sprouting wildly from his thin, beaker- shaped face, he affects a bemused-with-life persona, but comes on all bolshie. Happy to tell me he gets bored of doing plays that run longer than a month, he lacks the obligatory public relations riff most actors store up.

The one-time darling of Merchant/Ivory, he is currently to be seen on stage with Kevin Spacey in Howard Davies's new version of Eugene O'Neill's The Iceman Cometh; he also features in Richard Spence's light-hearted Different for Girls, as a motorcycle courier who falls for his old schoolchum- turned-transsexual.

Fame - which he calls "a bastard huge and all-consuming compromise" - is there for the taking, and for a self-confessed "lazy fucker", his prolific work-rate of late is attracting recognition. Apart from Girls, minor roles in the recently released Bent and Mrs Dalloway (an impressive display as the tormented Septimus Warren Smith) were slotted in between runs at the Old Vic and Queen's Theatre of David Rabe's intensely kinetic Hurlyburly, in which Graves ranted his way through three nihilistic hours. Add to that a stage version of Les Enfants du Paradis, and last year's Intimate Relations, and the disorganised act just doesn't wash.

"I've got it all wrong, haven't I?" he admits, "but I am undisciplined. I get out of bed late and get there as late as I can. I'm not very good at planning. I'm a drifter, really. An itinerant." Proudly adhering to a "lazily thought-out philosophy - if things are meant to be then they'll be", Graves hustles for no role, a policy that has seen him ping-pong between period drama and contemporary urban tales, replete with a social conscience, such as last year's dire The Innocent Sleep, in which he played a homeless Scouser. Flippantly suggesting he was attracted to Different for Girls because the Buzzcocks were on the soundtrack, he confesses to finding the subject of transsexualism interesting.

"I liked the extremity of the basic dilemma: you fall in love with your best mate, who changed sex. What does that mean, if you consider yourself a normal heterosexual guy? I do have that belief that basically we have a potential for a wide spectrum of latent behaviour. Your circumstances shape you quite a lot. If you're pretty open you can get in touch with an extraordinary array of character traits within yourself. Prentice genuinely falls in love, and it acts as a wake-up call to the stagnation of his life."

As much self-mocking as he is overtly critical of others' work, Graves felt the script to be "pat" at first, a reaction he has to a lot of treatments that come his way. He qualifies this by adding that the producers nearly always tell him "Well, that's because you don't understand it", a put- down he resigns himself to. Calling himself "uneducated", he perversely appears au fait with subjects ranging from Virginia Woolf's abuse as a child to Post Traumatic Stress Disorder. Graves' meticulous research for Mrs Dalloway - which included research at a south London hospital for stress-suffering Gulf War veterans - is an example of his ability to submerg himself into his role. A man who learns about life through his art, his veiled screen presence is more a testament to his dedication to the profession than a lack of ability. Mixing boyish charm with a vulnerable sex appeal, animation floats uneasily with lethargy in his performances, seemingly a result of "pat" script choices, and his diminishing interest in them, more than anything else.

Now 34, he grew up in Weston-Super-Mare with a father who often took him to the circus. There he landed his first job, as Tomato the junior clown. Not cut out for academia, Graves was sent to an educational psychologist in his teens, and spent a brief period at the Sylvia Young Stage School in London. Five years on, aged just 21, he landed the breakthrough role of Freddy Honeychurch in Merchant/Ivory's A Room With A View. Untrained, he became a staple element to late-Eighties English period drama, featuring in Where Angels Fear To Tread, A Handful of Dust and, memorably, as gamekeeper Scudder in Maurice. Keeping up appearances in the early Nineties, with his cuckolded son of Jeremy Irons in Louis Malle's Damage, and the King's Equerry in Nicholas Hytner's The Madness of King George, Graves has continued to manipulate misinterpreted perceptions of him.

"Because I'm called Rupert and I'm not from public school, at the time of A Room With A View and Maurice, people assumed I was, which was why I got called into Merchant/Ivory. "I think that's how the business works," he says, emphasising the point by warning a passing luvvie to never again call him "Rupey".

Forthcoming projects show no sign of change. To come is The Revengers' Comedies, alongside Sam Neill, Helena Bonham Carter and Kristin Scott Thomas, as well as Dreaming of Joseph Lees, a love story set on the Isle of Man, in which he plays "a one-legged geologist". The role allowed him the opportunity to work with Samantha Morton, recently lauded for her part in Carine Adler's remarkable Under the Skin. Playing the son of an anarchist, later racked by guilt for sending his mother to the electric chair, Graves saw the role as a chance to consolidate what he had learnt from working on Hurlyburly. As if kicking into gear, a torrent of energy springs from the man, breaking up sentences with missile noises as he demonstrates the adrenalin rush that performing live gives him.

"I don't know what acting is. I haven't a clue, mate," he concedes. "It's being honest with feeling. One of the joys of acting is looking at parts of yourself. You personalise that and then look at the circumstances around you... but I'm not very good at talking about acting."

`Different for Girls' opens today. `The Iceman Cometh' runs at the Almeida Theatre until 23 May.