Colloca was born in Milan to Loredana and Mario Colloca. Her first major film role was in Van Helsing, in which she played Verona, one of Dracula's brides. In September 2004, she married the Australian actor who played Dracula in that film, Richard Roxburgh. They have three children.

Colloca is an opera-trained mezzo soprano and worked as a musical theatre performer in Italy before becoming a film actress.