John Stamos has revealed that he once found his girlfriend Teri Copley naked in bed with Tony Danza.

In his forthcoming memoir, If You Would Have Told Me (which hits shelves Oct. 24), the Full House star looks back at meeting and instantly falling head over heels for the model and actress after a casual first date (the former couple were seeing each other for a brief time in the 1980s).

“She’s everything I’m looking for in a woman,” he recalls in the memoir. “She has an adorable daughter, Ashley, from a former relationship, and I love the idea of stepfatherhood. I’m starting to imagine our little family coming together. I’m dumbstruck and goofy in love. I could spend the rest of my life with her. Who knows if I’ll ever find love again? Why not take a chance?”

More than a year into their relationship, however, Stamos began to notice a change between them while he was away “doing car shows and gigs.”

“I call her from the road, but the girl who breathlessly picked up the phone after one ring is now giving me busy signals and dial tones,” Stamos writes. “When I get home, I call her throughout the day and into the evening. No response. Strange. We’ve gone from talking on the phone every few hours to silence.”

While he initially brushed it off thinking that Copley was at a modeling gig or audition, Stamos started to grow more and more concerned as time went on and he got no response. Remembering that Copley’s ex-husband, Chip Mayer, was in town for the weekend, he hopped in his car and drove to her home in the Valley.

However, when he arrived, he discovered the house had “no lights on” and “no movement behind the windows” but that there was a car parked in her driveway.

“A black 1957 Porsche 356 Speedster, vintage convertible. Strange. I shuffle to the car with my stomach sinking and take a quick look inside,” he writes in the memoir. “There’s a hairbrush, keys, boxing gloves, and a half-unrolled poster of my girlfriend, naked, barely covered by a white sheet. Half of her butt is showing. I’ve never seen this poster before.”

With the front and side doors of the house locked, Stamos remembered that he and Copley would sometimes sleep in the guesthouse, so he went to inspect it.

“The blinds are closed, but the door is slightly open,” he writes. “I take a peek inside and see four feet protruding from the shabby-chic, floral-print duvet that once kept me warm. My Tiny Dancer is in bed with Mr. Porsche Speedster. They are sleeping. I can’t tell who he is, but I recognize Teri’s ass barely covered by the sheets. It looks like her new poster.”

Stamos describes the moment as “my worst nightmare.”

“I try to hold back tears,” he writes. “Time slows until I’m frozen. I can’t breathe. A few tears roll down my face, and it pisses me off. They snap me out of my daze, and I feel angry and confused. I could explode.”

Stamos wasn’t sure what to do with the man sleeping with his girlfriend. “Do I pull him out of the bed by his hair, kick him in the nuts, and beat his ass?” he wondered. “She’s my girlfriend. Who is this piece of s—? He looks familiar. Content bastard. He rolls over, exposing his ripped abs and muscular body.”

Ultimately, he decided to “run like hell,” describing the situation as “not the time or place to save an ego that’s shot to s—.” But, before he left, he grabbed the poster in the car.

“I stare at the two-dimensional, half-dressed woman that I thought I knew. She’s signed the poster, with little hearts, ‘My Dear Tony, I’ll love you forever. XO, Teri,’” he recalls. “Tony? Who the hell is Tony?”

It wasn’t until he was on the drive home listening to Elton John that Stamos realized “the name of my rival.”

“Hold me closer, Tony Danza,” he writes.

Representatives for Danza and Copley did not immediately respond to EW’s request for comment.

In a later chapter of his memoir, Stamos credits Danza’s beloved 1980s show Who’s the Boss? with helping his own big sitcom Full House — which premiered a few years after Boss — gain steady viewership during its first season.

“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.”

Danza and Stamos played similar roles on their respective sitcoms. Danza starred as Tony Micelli, a quick-witted former professional baseball player who raises his daughter while working as a housekeeper, across eight seasons of Who’s the Boss? Stamos, meanwhile, played the exterminator by day, rock star by night Jesse Katsopolis on Full House and its recent sequel series, Fuller House. On the original show, Jesse helped raise his brother-in-law Danny Tanner’s (Bob Saget) three daughters: D.J. (Candace Cameron Bure), Stephanie (Jodie Sweetin), and Michelle (played by both Mary Kate and Ashley Olsen).

Stamos’ new memoir, If You Would Have Told Me, is out Oct. 24. Pre-order it here.

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