They seem to be good friends and their families have vacationed together. Jon was at his daughters bat mitzvah and I don't know if the other members were as only Jon was mentioned in the media article. That being said, David loves his side career. I recall an article where the director of Memphis(?) was being interviewed and said that he was talking to David and had mentioned that since Jon was a singer/actor, maybe he could be in the play. He might have been joking but David responded emphatically that it would be a bad idea and not to go there.