Venice, Italy - Dwayne "The Rock" Johnson said Monday he had turned his heavily muscled back on action movie roles to be able to express himself as an actor in his latest film The Smashing Machine which premiered in Venice.

The 53-year-old was the day's star attraction at the Venice Film Festival – his first appearance at a European festival – where he mixed with arthouse directors and independent movie fans on the Lido.

The Fast and Furious star told reporters that he'd taken on previous roles for commercial reasons and "the box office in our business is very loud and it can be very resounding and it can push you into a category and into a corner."

"I understood that, and I made those movies... some were really good and did well, and some not so," the wrestler-turned-actor confided.

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"I just had this burning desire and this voice that was saying, 'Well, what if? What if there is more and what if I can?'"

On paper, the role in The Smashing Machine by director Benny Safdie was tailor-made: Johnson plays wrestler Mark Kerr, a real-life former mixed martial-arts fighter in the 1990s and 2000s.

But Kerr – in a contrast to many of Johnson's previous roles – is a flawed and nuanced character with a sometimes toxic relationship with his girlfriend Dawn (Emily Blunt).

"The film isn't about fighting. It's a love story about Mark and Dawn and his relationship," Johnson said, while also revealing he had had to bulk up for the role at Safdie's request.

In its review, film bible Variety called Johnson a "revelation", adding that "he seems like a new actor."