Michael J. Fox Doesn't Want Taylor Swift Dating His Son

(Jeff Vespa/WireImage)

At last Sunday's Golden Globes, host Tina Fey joked to Taylor Swift, "stay away from Michael J. Fox's son," who attended the awards show with his father.

Now Fox is giving her the warning too. At a book party for Ann Leary's "The Good House," the "Back to the Future" actor told Vulture magazine he doesn't want Swift dating his 23-year-old son Sam.

"No. No … Just back off," Fox reportedly said. "I don't keep up with it all. But Taylor Swift writes songs about everybody she goes out with, right? What a way to build a career."

Swift recently split from One Direction's Harry Styles so she is on the market. If the 23-year-old showed up at his home, Fox said he wouldn't know who she was. But Fox might know if Swift wrote one of her notorious break-up songs about his son.

"Yeah, exactly," Fox said. "'Sam, You Piece of S***.' 'Oh … that was the girl you brought home!'"