Exclusive

Exclusive: Up All Night Welcomes Happy Days Vet Marion Ross -- Find Out Who She's Playing

Up All Night is fast becoming the Happy-est show on television.

TVLine has learned exclusively that — on the heels of Happy Days vet Henry “The Fonz” Winkler being cast as Ava’s fatherMarion Ross has been tapped to guest-star in an upcoming episode of the NBC comedy, playing …READ MORE