From one legendary guest-starring stint to another...

Coming off his Emmy-nominated turn as The Trinity Killer on Dexter, John Lithgow will debut as Barney's father on How I Met Your Mother this spring, making his first of two appearances on March 21.

Teases co-created Carter Bays to TV Line, which first published this photo: Barney will struggle to “reconcile who he hoped his dad would be and who his dad actually is.” We're guessing he'll also make us laugh a lot while doing so...