ALYSSA MILANO and her mother are feuding over her scandalous new series “Mistresses”!

In an amazing about-face, the former child star of “Who’s the Boss?” has gone from anti-porn crusader to portraying an adulterer who regularly sheds her clothes on the raunchy ABC drama.

The racy scenes have shocked and outraged her conservative mom Lin, says an insider.

“Alyssa’s mom never thought she would be starring on a show that glorifies adultery and promiscuity,” confided a source close to the 40-year-old star.

Based on a British TV show, “Mistresses” follows the lives of four friends and their intriguing romances – many of them illicit. Alyssa plays the role of Savannah “Savi” Davis, an unhappily married lawyer who cheats on her husband.

“Lin isn’t in charge of Alyssa’s career choices anymore, but she let Alyssa know she never would have allowed her to audition for a role like that,” said the source.

Doting mom Lin is especially sensitive to racy material because of a jarring 1998 incident in which Alyssa’s brother Cory found phony nude images of the actress on the Internet.

Alyssa’s mom was so upset she went on a crusade to clean up the Web.

But now Alyssa’s flaunting herself on network TV.

And despite her mother’s objections, Alyssa, who’s married and raising a 22-month-old son, is enjoying the challenging role.

“I look at Savi as being a really good person who makes a really bad decision and then has to deal with the repercussions of that,” the actress told an interviewer. “The biggest challenge was making her likable.”