United Kingdom, May 10 -- Melanie Hamrick has defended the 44-year age gap between her and fiance Sir Mick Jagger.

The former ballerina, 37, quipped that the Rolling Stones frontman, 81, is "younger" than she is as she discussed their relationship.

Melanie told Page Six: "He's younger than me.

"He's amazing, he really is."

The star has son Deveraux, eight, with the legendary rocker and explained that her boy has inherited his father's exuberant dance moves.

She said: "'It's amazing. It's natural, it's in his genes. No one taught him, no one influenced him. He moved like that before he saw any of his dad's concerts."

Melanie confirmed last month that she and Jagger have been engaged for "two or three years now" but are not in a rush ...