Lithgow will play Jerry, the long-lost father of Barney (Neil Patrick Harris), with whom he reunites and, in the second episode, joins for a wild night out on the town.
A Tony Award winner for Sweet Smell of Success and The Changing Room, Lithgow holds three Emmys for his work on the sitcom "Third Rock from the Sun" and two for guest appearances on "Dexter" and "Amazing Stories." Additional stage credits include All My Sons, Dirty Rotten Scoundrels, The Retreat from Moscow, M. Butterfly, Requiem for a Heavyweight, Beyond Therapy, Bedroom Farce, Anna Christie, Comedians, Trelawney of the Wells and My Fat Friend. He is an Academy Award nominee for "Terms of Endearment" and "The World According to Garp."
"How I Met Your Mother" airs Mondays at 8 PM ET on CBS.