It was all going so well for James Gray. His romantic drama Two Lovers was getting the best reviews of the 39-year-old writer-director’s four-film career. They loved it too in Cannes, where this moody Brooklyn-set tale of a tremulous love triangle was nominated for the prestigious Palme d’Or.

A good performance, meanwhile, from Gwyneth Paltrow, complete with a coolly erotic breast-baring scene, ensured that popular interest was appropriately piqued. But then last month, on The Late Show with David Letterman, disaster struck. The movie’s male lead, Joaquin Phoenix, who was supposed to be promoting Two Lovers, simply hid behind an unruly beard, chewed gum, sighed and stuttered and ultimately convinced audiences everywhere (the clip became a YouTube phenomenon, with 7.5 million hits so far) that his acting career was over, that Two Lovers didn’t matter, and that the Joaquin Phoenix wacky train was truly in town.

“It’s like, Letterman was trying to get the movie out there, but the only thing that’s out there now is a crazy person with a beard making a fool of himself!” says Gray, still seething today at the “circus” surrounding Phoenix. The actor, a veteran of three of Gray’s movies now, claims to be leaving the world of acting to become a rapper, albeit one with a camera-wielding brother-in-law, Casey Affleck, in tow. Affleck, married to Phoenix’s sister Summer, is shooting a documentary about Joaquin’s extraordinary transition.

Gray spits at the name, calling him a “clown”. “I have no idea what the hell that guy is shooting,” he says. “The whole thing is not to my taste, and I’ve let Casey know this.”

However, speculation that Phoenix’s transformation is a hoax seems misplaced, Gray says. “Towards the end of the movie he kept saying, ‘I’m tired, I’m tired, I don’t want to act any more. I’ve been doing this for 30 years and I can’t take it!’ And I thought, at the time, he was just tired. But I must say, I’ve seen him in his house, and he has his own recording studio that he built right there. So if this is a hoax, then it’s the most elaborate thing that I have ever seen.”

None of this, he adds, is helping his movie, which is certainly his most accessible and moving film to date. The story of a Brighton Beach no-hoper called Leonard (Phoenix) who drifts between the homely and accessible Sandra (Vinessa Shaw) and the exotic and perplexing Michelle (Paltrow) is a touching tale of minutely observed emotional truths, while Gray’s previous movies, such as the crime dramas The Yards and We Own the Night, have often veered towards grand operatic tragedy.

They are all, to different degrees, autobiographical, he says, before describing his Russian American heritage (the family name, Greizerstein, was anglicised by a customs official at Ellis Island) and his tough childhood in Queens. There, he lost his mother to brain cancer when he was still a boy, and was raised by a father who ran a subway maintenance company and had little time for Gray’s precocious movie-making ambitions (sparked by a viewing, at 10, of Apocalypse Now). “He used to say to me, ‘You’ll never make it! You’ll never do it!’” he says, adding with a sigh, “I have a good relationship with him now, but I think it’s a terrible thing to tell a child that they can’t pursue their passion.”

Undaunted, Gray eventually won a scholarship to the University of Southern California film school. He returned, nonetheless, to New York for inspiration, and for the autobiographical subjects and characters that would fill his films — the matriarch Irina, for instance, played by Vanessa Redgrave in his debut movie Little Odessa, is dying from brain cancer.

These days Gray, now based in LA, keeps hallowed Hollywood company, and is slowly shifting his focus away from his beloved East Coast milieu. Martin Scorsese, for one, has asked him to direct the French Resistance drama And There Was Light (about the real-life blind Resistance hero Jacques Lusseyran), while Brad Pitt will star in and produce his next movie, The Lost City of Z, about the British archaeologist Colonel Percy Fawcett (the inspiration for Indiana Jones). “He’s got to master his British accent,” he says of Pitt. “I’ll be very obsessed if he gets a single syllable wrong in the entire movie.”

Elsewhere, heavy-hitting actors such as Paltrow are attracted to Gray because of his increasing cachet as a film-maker of serious intent. Indeed, working with Paltrow had its surreal moments, Gray says, especially when it came to shooting the now infamous “breast scene” — Paltrow’s Michelle, seducing Leonard from the opposite side of an apartment courtyard, blankly exposes herself to him. “She said: ‘I don’t think I can do that. I’ve had two children and I don’t think I look good any more. You can come into my trailer and I’ll show you my body, and if you think it looks OK, then I’ll do it.’ So she did, she undressed, and she looked great. I was like, ‘You look sensational! What are you worried about?’ ”

Gray himself, who is married to the photographer Alexandra Dickson, with two young children and a third on the way, says that he has yet to make his true movie statement, his passion project. “It’s an epic movie about the Russian Revolution of 1917, but it’ll never get done,” he says, groaning. “It’s too big and too expensive.”

In the meantime, after everything that’s happened with Two Lovers, if the whole Joaquin Phoenix circus is revealed to be a hoax, how will he feel? “If it is shown to be a hoax, then that’s great, because Joaquin will come back to acting. And he is something special. But if it isn’t, ye know, I think he needs, well, help.”

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