"Yes, of course it's true," Martinez told the Miami Herald over the weekend when he was in town for the opening of his new restaurant Villa Azur.
Martinez also wanted it known that their engagement ring is being designed by Robert Mazlo of Paris, "a real artist" whose family has designed rings for kings and queens for centuries, he said.
"There is a jeweller taking credit for doing the ring and it's a lie! They have nothing to do with this," he said.
Martinez and Berry met during the filming of "Dark Tide" in 2010.
Berry has been married twice before and has a three-year-old daughter with Canadian model Gabriel Aubrey.
Known for the "X-Men" movies and her role as Jinx in the James Bond flick "Die Another Day" (2002) with Pierce Brosnan, Berry won the Oscar for best actress in 2002 for her role in "Monster's Ball."
46-year-old Martinez won a César award, the French equivalent of the Oscars, in 1994 for his role in "Un, deux, trios, soleil".
He came to Hollywood's attention with his performance in Julian Schnabel's "Before Night Falls" in 2000, in which he played opposite Javier Barden and Johnny Depp.
Paris-born Martinez has dated a string of models, actresses and singers including Kylie Minogue and Mira Sorvino.