He later took theater courses at Montbéliard, and went on to star in more plays, including Jesus Christ Superstar and The Umbrellas of Cherbourg.
He started learning how to play piano at the age of 3.
He dubbed over Arnold Schwarzenegger in the French versions of all his films from 1987.
Beretta voiced programme trailers on the French channel 'Sci Fi', and, between 2000 and 2008, he was the station voice of the national adult contemporary radio station RFM.
He performed in his first play, Copain Clopants, in 1966. Catherine Allégret, who was in the audience, introduced Beretta to Marcel Camus, who put Beretta in his first film role in A Savage Summer.