Richard Thomas, star of “The Waltons,” knew it wouldn’t be easy to prove to audiences that he could play characters other than John-Boy Walton once his gig was up.

“I figured, I’d been in the show for five years,” the actor exclusively told Page Six in a new interview. “It was going to take at least five years to sort of do enough work to start to balance the scales.”

Thomas, who left the hit ’70s TV series after five seasons, was quick to stress that he “adored” the show.

“I have nothing but only incredible gratitude, affection and fond memories. It was a wonderful piece of television for its time,” he gushed, noting that the series aired when there were only three broadcast networks and when TV audiences were huge.

“The reach of that was phenomenal,” he continued, “and hard for people to understand today.”

The success of “The Waltons” notably included lots of attention from female fans.

“It was great!” Thomas enthused, “and it was the ’70s.”

The CBS series, which ran from 1972 to 1981, centered around a rural family during the Great Depression and World War II.

Thomas played the beloved role of John-Boy Walton, the oldest of the clan, who dreamed of becoming a writer one day.

The actor, who was was born and raised in New York City, went on to star in shows like “It” and made guest appearances in a slew of other series. Thomas eventually returned to his first love, the Broadway stage, where he made his debut in “Sunrise at Campobello” when he was only 7 years old.

He was nominated in 2017 for his turn in “Little Foxes,” and later portrayed Atticus Finch in the 2022-2024 tour of “To Kill a Mockingbird.”

Thomas also had a delicious role as the head of the FBI Counter-Intelligence in “The Americans,” which he raved about to Page Six.

“I loved it because it was kind of counterintuitive casting for me,” he explained. “[It] gave me really a wonderful opportunity to play a rather enigmatic character who sometimes you thought was OK, sometimes [you] thought he was just a d–k, you know?”

Thomas can currently be seen in “The Balusters,” a raucous comedy about a Neighborhood Association that descends into chaos when a newcomer suggests installing a stop sign in the enclave’s prettiest block.

The Post’s Johnny Oleksinski gave the show a raving review, calling it an “engrossing and enjoyable watch.”

During another portion of the interview, Thomas joked to Page Six about his upcoming 75th birthday on June 13. While he still appears decades younger, he swears he hasn’t had any work done.

“Come on!” he exclaimed, noting that foreheads are “one of the most expressive parts” of one’s face.

“I don’t want to freeze any of it,” he continued, “I mean, it’s falling apart, but what the hell?”

Thomas laughed when Page Six suggested he could launch a skin-care line, replying, “You’re very kind. You made my day!”