Are Hayes' & Gellar's TV Returns Risky?

Fans are eagerly awaiting the series return of some big stars, from Buffy the Vampire Slayer's Sarah Michelle Gellar to Will & Grace's Sean Hayes, but how risky is it for the actors' careers?

Among the many veteran actors returning as series regulars for the upcoming 2013-14 season is West Wing's Allison Janney, who will co-star alongside Anna Faris in the comedy series Mom.

PICS: 10 Most Promising New Fall TV Shows

Two stars will be aligning for the NBC comedy Sean Saves the World: Will & Grace's Sean Hayes and Linda Lavin of the '70s/'80's sitcom Alice.

As Robin Williams stars in his first television series in over thirty years in The Crazy Ones, he is joined by Buffy the Vampire Slayer star Sarah Michelle Gellar, whose claim-to-fame series concluded in 2003.

VIDEO: Williams & Gellar Preview New Series 'Crazy Ones'

Watch the video for an in-depth sneak peek at the big stars who are taking the risk of returning to TV in a new comedy series.