By Mike Collett-White

CANNES, France (Reuters) - It is only day two, but the Cannes film festival has already uncovered a breakout star in Belgian Matthias Schoenaerts, who has earned critical acclaim and plenty of swoons for his portrayal of tough guy Ali in French drama "Rust and Bone".

Schoenaerts is not new to the big screen -- he has appeared in more than 20 films including "Bullhead", nominated for a foreign language film Academy Award earlier this year.

But for thousands of journalists and critics in Cannes for the annual cinema showcase, a press screening on Thursday of the moving love story Rust and Bone ("De Rouille et d'Os") was their first look at the physically imposing 34-year-old.

Within minutes of the movie ending, Schoenaerts was being asked about his prospects in Hollywood.

"It's funny you say so, because last week they called me for 'Rambo 34', and I said I'll do it if I get 35 and 36 as well," he joked at a press conference.

"There's definitely stuff moving in the States, but I've got time, I'm not in a hurry. I'm quite young I guess."

He may hope to replicate the success of French actor Jean Dujardin, who was little known outside France until the Cannes world premiere last year of "The Artist" which set him on a path to global fame and a best actor Oscar.

AVOIDING MELODRAMA

In Rust and Bone, Schoenaerts plays the central character Ali, a gruff hulk of a man who befriends a Marineland employee called Stephanie, played by Oscar winner Marion Cotillard, after she loses her legs in an accident at work.

Down on his luck and sleeping with five-year-old son Sam in his sister's garage on the southern French coast, Ali lives hand-to-mouth before taking up brutal but lucrative bareknuckle fighting for extra cash.

It takes a major shock to shake him from his emotional torpor, and at the film's end there was warm applause from the notoriously picky critics and reporters in Cannes.

Largely positive early reviews focused on the performances, although some faulted a plotline they felt was implausible.

"Schoenaerts is as good as Cotillard at avoiding the trap of melodrama, and they sustain a film that's not as obviously notable as 'A Prophet' but, much more quietly, makes a considerable mark," wrote Derek Malcolm in London's Evening Standard.

Cotillard likened her co-star to Leonardo DiCaprio and Daniel Day-Lewis, while one online review drew comparisons between Schoenaerts and rising British star Tom Hardy.

Schoenaerts admitted feeling anxious about acting with Cotillard, who was in character when he first met her on set.

"I saw Marion before the rehearsal, she was in a wheelchair, she looked totally depressed and I thought ... 'It's not going to work out very well with Marion' and I thought 'What do I do? Should I talk to her?'"

Rust and Bone is loosely based on a collection of short stories by Craig Davidson, and is one of 22 movies in the festival's main competition.

French director Jacques Audiard wowed audiences with his gritty prison drama "A Prophet" in 2009, and although in Rust and Bone he swaps cramped, dark cells for bright sunshine and expansive seascapes, he again tells the story of a man who is down and out and must fight for survival and redemption.

Audiard said he could not have made the movie 10 years ago, because modern special effects allowed him to recreate Stephanie's impressively realistic severed limbs.

"Now things are much easier," he said. "You just (use) special devices and you can do away with a large section of the legs. Now you can use a handheld camera to produce special effects. It's tremendous progress."

(Reporting by Mike Collett-White)