Sunday's episode of The Simpsons, "Married to the Blob," not only spotlights a blossoming relationship between Comic Book Guy and a manga creator (which naturally threatens to be ruined by Homer), but also features guest appearances by Stan Lee and Harlan Ellison.

The Hollywood Reporter has debuted a featurette that goes behind the scenes with the two legends; it's Lee's second visit to Springfield, but for Ellison, it's a new experience.

"I was here 12 years ago," explains Lee, who plays himself as a Watcher-type character, "and I think I impressed them so that after 12 years they figured they had to have me back."

Lee previously appeared in the 13th-season episode “I Am Furious (Yellow).” The Simpsons airs Sunday at 8 p.m. ET/PT on Fox.