The 30-year-old called the "Bad Teacher" actor her "fiance" for the first time on the Jay Leno show, reported Sun Online.
Talking about a trip to Puerto Rico, she said, "I was visiting my fiance there. He's shooting a film there. So I'm vacationing. I'm having the best time of my life. It's fantastic," she said.
The couple were thought to have got engaged last December, after a five year relationship but they have made no official announcement and have never talked about the engagement.
The actress was recently pictured wearing a gold necklace with the name 'Justin' as she went out and about in LA.