Ulliel gained international attention for his performance as the famous cannibal in Hannibal Rising and had a leading role in the upcoming Marvel TV series Moon Knight.
His family confirmed the death in a statement given to AFP by his agent.
Ulliel won a César – the French equivalent of an Oscar – for best actor in 2017 for It’s Only the End of the World in which he starred alongside Marion Cotillard and Lea Seydoux.
He had already taken home a Cesar in 2004 for most promising actor after appearing in the World War I drama A Very Long Engagement alongside Audrey Tautou.
He starred in Saint Laurent, one of two biopics about the legendary designer to be released in 2014, though he lost out at the Cesars to the star of the rival film, Pierre Niney.
You can find a round-up of his best film roles HERE.