Henry Winkler is sharing which former screen partner didn’t leave the best impression on him.

While appearing at a recent fan expo in Tennessee, the 80-year-old actor spoke about the camaraderie on set of “Happy Days,” explaining “on our set, there was no stardom,” and how one guest star failed to mesh with the rest of the cast.

“We were an ensemble. We worked hard at making it funny every week,” he said. “One guy came on as a guest star, and then he was brought back a few times, and he would mention his fan mail, and I said, ‘You don’t want to talk to me about fan mail, I got 50,000 letters a week.’”

He then explained to the actor that “we don’t talk about that on the set” and that “we are all here as one.”

Despite the warning, Winkler said the actor “kept doing it,” later calling the guest star “an a–back.” While he didn’t name names, he mentioned that the character the actor portrayed was named Eugene.

Winkler played Arthur “Fonzie” Fonzarelli on the hit sitcom throughout all of its 11 seasons, from 1974 to 1984. After getting his big break on the show, he went on to enjoy a successful career in both film and television, earning a Golden Globe nomination for “Heroes,” and starring in “The Waterboy,” “Holes” and “Click.”

After years in the industry, Winkler is still having new experiences on set, as he recently filmed his first nude scene for the first episode of the third season of “Loot.”

“Maya Rudolph is one of my favorites. She is [a] brilliant person and a lovely person. So, when she asked me to be on the first episode of the third season of ‘Loot,’ I didn’t even ask to read the script,” he explained.

He then explained that when he went to his first costume fitting, he was shocked to find “a silk robe that went to there,” he said while pointing to his upper thigh. “There was nothing else.”

“And then we did it in January on the beach. And I want to say the wind came from every direction,” he said. “Parts of my body, large and small. … It was so cold. I was in shock. But then I was with Maya and her wonderful cast.”

While he won two Golden Globe Awards for playing Fonzie, Winkler didn’t win his first Emmy Award until 2018, when he was rewarded for his work on the hit show “Barry.”

He starred on the show as Gene Cousineau, an acting coach who finds himself striking a friendship with a wanted assassin, played by Bill Hader, for four seasons.

“Be yourself, be honest about your ability, prepare so that you are not a flash in the pan,” he said backstage after his win, per Variety.

“When I first started here in Hollywood … I thought of myself as a tree or sapling. I planted. I wanted to grow and be strong until I couldn’t do this anymore. And what a great tree it is.”