Zara Phythian, 36, who starred in Marvel movie Doctor Strange, plied the teen with alcohol in a three-year reign of terror. Along with husband Victor, she abused the girl in the 2000s.
Phythian, from Mansfield, threatened her to keep her quiet.
The couple were each found guilty of 14 counts of sexual activity at Nottingham Crown Court.
They will be sentenced at a later date.
