Knock-out was released in the year 1939。Knock-out is also called as Invitation to Happiness, Invitación a la felicidad。

Trainer Pop Hardy thinks his heavyweight boxer 'King' Cole could be champ...some day; he wants to sell a half interest in Cole to his rich friend Wayne. Wayne's daughter Eleanor is disdainful, but brash Cole manages to get under her skin. Can a society dame and a mug find happiness together? And can she wait for his slow rise to fame?

Knock-out actors and actresses include Fred MacMurray, Irene Dunne, Mack Gray。