From Muppet Wiki

Chuck Close is an American artist of contemporary portraiture famous for his photorealistic paintings of a number of modern-day artists, sculptors and writers, including composer Philip Glass.

He appeared in a segment for Sesame Street with Big Bird in which one of his self-portraits is analyzed by a group of kids in voice over as the camera pans out from the painting. (EKA: Episode 3968)

In another segment, he similarly shows Big Bird his daughter Emma's favorite painting, a portrait of her. (EKA: Episode 3962)