The TV show 'Mork and Mindy' was a spin off from which American sitcom?

Mork & Mindy is an American sitcom broadcast from 1978 to 1982 on ABC. It stars Robin Williams as Mork, an extraterrestrial who comes to Earth from the planet Ork in a small, one-Orkan egg-shaped spaceship. Pam Dawber co-stars as Mindy McConnell, his human friend and roommate.

The series is a spin-off of the sitcom Happy Days. The character of Mork is played by a then-unknown Robin Williams, who impressed producer Garry Marshall with his quirky comedic ability as soon as they met. When Williams was asked to take a seat at the audition, Williams immediately sat on his head on the chair and Marshall cast him on the spot, and later wryly commented that Williams was the only alien who auditioned for the role.