John Stamos may have lost his dream girl to a sitcom heartthrob, but a light was waiting to carry him to success.

The “Full House” actor is opening up about the demise of his relationship with actress Teri Copley in his upcoming memoir “If You Would Have Told Me.” Stamos alleges the “We Got It Made” star cheated on him with actor Tony Danza.

Despite his head-over-heels courtship with Copley, Stamos writes that the actress began to give him the cold shoulder after he returned from touring with car show appearances and performing with the cover band Papa Doo Run Run.

Concerned about Copley’s lack of communication, Stamos headed over to his then-girlfriend’s house to check on her. Upon arriving at Copley’s home, Stamos noticed a car parked in the driveway.

“I shuffle to the car with my stomach sinking and take a quick look inside. There’s a hairbrush, keys, boxing gloves and a half-unrolled poster of my girlfriend, naked, barely covered by a white sheet,” Stamos writes. “I’ve never seen this poster before.”

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After being unable to open the front or side doors to Copley’s house, Stamos went to the “Brain Donors” actress’s guesthouse, where he found “four feet protruding from the shabby-chic, floral print duvet that once kept me warm.” Stamos wasn’t able to recognize the man Copley was in bed with, referring to him as “Mr. Porsche Speedster” for the vintage convertible parked in Copley’s driveway.

“My heart is beating out of my chest,” Stamos writes. “My mind is racing, and the room is spinning. I feel like throwing up all over her white shag carpet. It’s my worst nightmare.”

Just before leaving Copley’s home, Stamos grabbed the poster of Copley that was inside the Porsche for a closer look. The poster was signed by Copley with the message, “My Dear Tony, I’ll love you forever.”

While driving home and listening to the Elton John song “Tiny Dancer,” Stamos says he realized the identity of Copley’s lover. “I mouth the words to his most famous lyrics and realize the name of my rival, ‘Hold me closer, Tony Danza.’ ”

USA TODAY has reached out to representatives for Copley and Danza for comment.

In a twist of fate, Stamos later writes that Danza played a pivotal role in the trajectory of his acting career. After an underwhelming ratings performance in its first season, Stamos’ show “Full House” was paired with Danza’s hit sitcom “Who’s the Boss?” on the ABC lineup, which helped “Full House” find a bigger audience.

“If you would have told me the day I walked into that room and caught my true love in bed with another guy that his show, ‘Who’s the Boss?’, would launch Full House into a bona fide hit, making me a household name,” Stamos writes. “Well, what can I say? Thanks, Tony Danza.”

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