The Impossible Dream is the tenth episode of Season 7 of Three's Company, and the 138th overall episode of the series. Written by Shelley Zellman and directed by Dave Powers, it first aired 14 December 1982 on ABC.
To help give Jack's business a boost, Larry suggests he has a friend who would play the guitar at the bistro for free. Jack tries the guitarist out, only to find the vocalist is Larry! Although Jack thinks Larry sounds a lot like a Las Vegas casino reject, the customers apparently love him! Jack makes Larry's dream come true by telling him he can sing every night. However, when the following evening Larry proves to be a calamity, Jack realizes that the previous night Larry had filled the restaurant with a lot of his friends, cronies and girlfriends. The girls can't understand how Jack or anyone ever bought Larry's act.
Anyway, Larry is brought back down to earth the next few nights, when real customers come into the restaurant are turned off by his singing and exit the restaurant in droves! Jack is then not only saddled with the still difficult task of telling Larry he's fired, but also with the more difficult task of telling Mr. Furley, who helped out in the kitchen, the same after he messes up one of the filet mignon orders by putting ketchup on it!