Jackson debuted on the show Nov. 12 in a recurring role as a street performer hired for the fictional sketch comedy show "TGS."
He is currently appearing as Woody Mahoney in the Broadway revival of Finian's Rainbow at the St. James Theatre.
To view the Christmas episode of "30 Rock" (Jackson's singing entrance is eight minutes and ten seconds into the episode), click here.
“Secret Santa” and other episodes of “30 Rock” can be viewed on hulu.com.
— Allison Klamkin