From Muppet Wiki

Jane Hunt is the mother of Richard Hunt. A resident of Manhattan, she had a cameo as one of the Sardi's customers in The Muppets Take Manhattan. In Jim Henson: The Works, Jane Hunt recalled her son's excitement after auditioning for Jim Henson, and how in high school, he used to perform puppet shows for the children of her friends.

She contributed her memories of her son on episode 41 of the MuppetCast.