Jon Hamm has been to confirmed to guest star on an episode of Spongebob next year. Jon Hamm will play the role of Don Grouper – a charismatic head ad executive of the ad agency Grouper, Goby & Koi. His sharp mind and devastating charm make him an irresistible force. When Don’s in the room everyone laps up his words like overpriced organic honey. In the episode, Mr. Krabs goes to Don for help as Mr. Krabs tries to launch his line of frozen Krabby Patties. More details will be coming later. In the meantime here is a concept sketch of Don Grouper.