Joey's agent Estelle
We just watched the DVD extras for Season 8, including the "Friends of Friends" section where they interview some of the guest stars. I was flabbergasted to see and hear the real June Gable, who played Joey's agent Estelle. It's not so much her face that was different, it's more what she does with it
She explained that she auditioned for the role twice. After being rejected when she played it straight the first time, she was advised to try again with more "character." So in addition to wearing a wig, she added a strong accent, distinctive facial expressions, and a bunch of eccentric "business" -- and really wowed them! The role was written as a blank canvas, and Gable made it her own.