Was Vin Diesel a trained ballet dancer?

No, Vin Diesel was not a trained ballet dancer. While he is known for his physicality and action roles, his background is in theatre and filmmaking.

He studied acting at Hunter College in New York City, and his early work was primarily in theatre. He also wrote, directed, and starred in the independent film "Strays" (1997), which launched his film career.

There is no documented evidence of him ever having formal training in ballet.