Silver Spoons(1982)

Wealthy, young-at-heart business owner Edward Stratton III is stunned to discover his brief marriage several years ago produced a son, Richard Bluedhorn-Stratton, now 12 and standing in Edward's living room, wanting to live with the father he never knew. Although Edward's first impulse is to send Ricky to boarding school, he soon relents and let his son move in with him and Kate, his love-struck secretary.