John Stamos recalls finding girlfriend in bed with Tony Danza: ‘Worst nightmare’

John Stamos claims he caught his then-girlfriend and model Teri Copley in bed with fellow actor Tony Danza during their short-lived romance in the 1980s.

In his memoir “If You Would Have Told Me,” out Tuesday, the “Full House” alum revealed that he discovered Copley cheating with the “Who’s the Boss?” star one night.

“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, 60, wrote in an excerpt obtained by Entertainment Weekly. “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.”

Initially brushing it off as Copley, 62, being busy at a modeling gig or an audition, Stamos wrote that he began to get concerned as time went on.

Remembering her ex-husband was in town, Stamos said he hopped in his car and drove to her place.

Upon arrival, Stamos discovered the house had “no lights on” and “no movement behind the windows” despite a car being in the 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,” Stamos wrote. “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.”

Unable to enter the house from either the front or side doors, Stamos said that he remembered that he and Copley used to sleep in the guesthouse in the backyard.

“The blinds are closed, but the door is slightly open,” he continued. “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 a– barely covered by the sheets. It looks like her new poster,” the “You” star recalled, describing the moment as “my worst nightmare.”

“I try to hold back tears,” he shared. “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 said he debated what to do next.

Ultimately, Stamos revealed that he decided to “run like hell” — but not before stealing the poster from the mysterious 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,’” Stamos noted. “Tony? Who the hell is Tony?”

It wasn’t until Stamos was speeding home, and with a little help from a catchy Elton John tune, that he realized “the name of my rival.”

“Hold me closer, Tony Danza,” Stamos emphasized.

The Post reached out to Danza, 72, Stamos and Copley for comment.

The ugly claim is one of several the Hollywood hunk drops in his explosive new memoir.

The “Grandfathered” star reveals he “hated” ex-wife Rebecca Romijn, 50, after their nasty divorce in 2005.

“My first marriage was shattering to me. I was shattered for way too long, too,” Stamos told People. “I mean, a year, okay, good. But it went on [for] years and years.”

“In my mind back then, she was the Devil, and I just hated her,” he continued. “I couldn’t believe how much I hated her, and it ruined my life. Looking back, and I talk about it [in the book], because it’s one of the steps in AA where the fourth step is you lay out all your grievances, everything that people did to you. I go like, ‘None.’”

Stamos also alleged he was sexually assaulted by his babysitter as a child.

“I didn’t want the headlines to be that, and I didn’t want the book to be over that,” Stamos wrote. “It was a page or something, but I felt I had to talk about it. It was weird. It was something that, I think, I was probably like 10 or 11 [when it happened]. I shouldn’t have had to deal with those feelings”

If you or someone you know has been sexually assaulted, please contact the National Sexual Assault Hotline at 1-800-656-HOPE (4673) or go to rainn.org.