Brett Gelman stars as the enigmatic Mr. K, a participant in the support group meetings in NBC's new comedy series "Go On." It's not quite clear what Mr. K is grieving. But as badly as his fellow group members would like to know, no one is willing to get close enough to ask.

Gelman, an Upright Citizens Brigade regular, is currently co-starring in Adult Swim's "Eagleheart."

He has appeared in "The Other Guys" directed by Adam McKay and on both seasons of "Funny or Die Presents." Additional credits include guest-starring roles on "The League," "Curb Your Enthusiasm" and "Bored to Death." Gelman is slated to appear in the upcoming series "In Betweeners."