McKean will play the father of Dave Rose (played by Zachary Knighton) and Mullally will reprise her previous role as the mother of Penny Hartz (played by Casey Wilson).

McKean is currently appearing in the Public Theater's production of King Lear and will co-star this spring in the Broadway revival of The Best Man. Mullally has appeared on Broadway in Young Frankenstein, Grease, and How to Succeed in Business Without Really Trying, and is well known for her Emmy Award-winning work as Grace Walker on Will & Grace.

Happy Endings also stars Eliza Coupe, Elisha Cuthbert, Adam Pally, and Damon Wayans, Jr.