In a July 18, 2016 file photo, actor Scott Baio speaks during the opening day of the Republican National Convention in Cleveland. Credit: J. Scott Applewhite | AP

Actor Scott Baio, appearing Wednesday on ABC’s “Good Morning America,” vehemently denied his former “Charles in Charge” castmate Nicole Eggert’s accusations that he repeatedly sexual abused her when she was a teenager.

“I don’t know if you’ve ever been on a sitcom set,” Baio told anchor Amy Robach, “but on any given day, on every day and especially (on) ‘Charles in Charge’ – which was like a picnic every day, it’s one of my favorite jobs I’ve ever done – there’s teachers, parents, family, crew, producers, my dad. How any of this could’ve happened is absolutely impossible.”

The controversy began Saturday morning, when Eggert, 46, tweeted that she and Baio, 57, had sex “in his garage at his house when I was a minor.”

On NBC’s “Megyn Kelly Today” Tuesday, Eggert said that Baio had sexually harassed and abused her throughout her years on the ’80s CBS sitcom, which began when she was 14. He started to profess his love to Eggert then, she said, alleging that the abuse began before her 15th birthday, when they were in his garage and he “reached over and penetrated me with his finger.”

Eggert added that the abuse was “probably once a week,” and that Baio groped and fondled her. She alleged that other cast members saw him try to kiss her on set.

“It wasn’t a hold-me-down, rape me situation,” she said, “but I was 17 … I wasn’t ready to tell my story. For me it was always protecting the show.”

On “Good Morning America” Wednesday, Baio admitted to Robach that they had one particular sexual encounter, which Eggert initiated (while Eggert had told Kelly the previous day that she never initiated anything). But he denied that the additional incident in the garage ever occurred.

“I have no idea what that means,” he said, nervously laughing. “No idea. You can’t just keep making up different things.”

Eggert previously mentioned having sex with Baio in a 2013 interview on Nik Richie Radio, during which she had indicated that she was 18 when the incident occurred.

But on Wednesday morning, Robach read a statement from Nik Richie, and noted that the radio host and Eggert share a manager.

“Nicole was distraught after the interview … She told me it was much worse than she described on air,” the statement read. “She said, ‘He molested me as a child and I didn’t know any better.’ I can vividly remember that statement. It’s not one you would forget.”

Baio responded to Robach, “I find it interesting, Amy, that the moment that her first allegation – that we had sex when she was 17, which was not true – as soon as it was proven to be 100 percent false, she comes up with a new story where something happened once a week for years.”

Baio, best known for playing Chachi Arcola in the TV series “Happy Days” and its spinoff, “Joanie Loves Chachi,” rose to public prominence again recently after endorsing then-candidate Donald Trump in 2016. He spoke at the Republican National Convention in Cleveland and told the Hollywood Reporter afterward that he was getting “beat up a bit” for his actions.

“Mainly on Twitter, and the media,” he elaborated. “And again, these people think it bothers me. It doesn’t bother me. It’s laughable.”

On Wednesday, the actor condemned the way social media responds to accusations of sexual misconduct. After Robach asked if he was concerned Eggert may take her claims to the police, Baio responded that he wasn’t and encouraged the actress to take her case “through the proper channels.”

“You put up allegations like that, and it becomes like wildfire,” he said, adding, “My 10-year-old daughter does not need to be hearing about this from friends at school, these false allegations. Her job is not to defend me. Her job is to be 10 years old, and that’s why this has got to stop.”