Laughing Gas — P.G. Wodehouse

Joey Cooley is a golden-curled child film star, the idol of American motherhood. Reginald, Third Earl of Havershot, is a boxing blue on a mission to save his wayward cousin from the fleshpots of Hollywood. Both are under anesthetic at the dentists when something strange happens—and their identities are swapped. Suddenly Joey can use his six-foot frame to get his own back on his Hollywood persecutors. But Reggie has to endure everything Joey had to put up with in the horrible life of a child star—including kidnapping.