It's a Boy on AllMovie

It's a Boy was freely adapted from a German play by Franz Arnold and Ernest Bach. On the eve of his marriage to Anita Gunn (Heather Thatcher), Dudley Leake (Edward Everett Horton) is confronted by Joe Piper (Albert Burdon), who claims to be Dudley's illegitimate son. Best man James Skippett (Leslie Henson) smells a rat, especially when Joe demands money for his silence. Investigating on his own, Skippett learns a few awful truths and saves the day. Heavily made up as an old duffer, Edward Everett Horton garners most of the film's laughs, keeping the very thinnish plotline afloat.