Mary Kay Letourneau (search) is engaged to her former student — and she has the ring to prove it.

The teacher, convicted of child rape for beginning a sexual relationship with Vili Fualaau (search) when he was 12 and she was 34, showed off her new bauble Monday night in a television interview.

Letourneau would not reveal the date of the nuptials — but revealed she would have flunked Vili, the father of two of her children, if he had not been her lover.

"He was very disruptive [in class]," she said.

When asked if she would have failed the young boy had they not been lovers, she answered, "Yeah, I would have."

Fualaau is now 21 and Letourneau is 42.

She served a six-month sentence for rape — and then another 71/2 years for defying a court order for seeing Fualaau.

Although she's estranged from her four children from her first marriage, Letourneau insisted that she has no regrets about the affair.

"I'm healthy. My children are healthy," she said. "And I have Vili."