Robin Williams and Sarah Michelle Gellar in "The Crazy Ones"
Robin Williams and Sarah Michelle Gellar in "The Crazy Ones"

Check out the fun and, er, acoustic promo for "The Crazy Ones," a new TV comedy series with the tantalizing cast of Robin Williams, Sarah Michelle Gellar and James Wolk (aka the inscrutable Bob Benson of "Mad Men"). Watch below.

The series follows, per IMDb,  "a confident young copywriter" (that would be Wolk -- clearly his "Mad Men" casting is paying off) at an ad agency run by Williams, whose daughter is Gellar. Kelly Clarkson also stars.

"The Crazy Ones" premieres on September 26 on CBS.