Barry Williams warned about chemistry with ‘Brady Bunch’ co-star Maureen McCormick

Sibling love.

Barry Williams admitted that he had “chemistry” with his “The Brady Bunch” co-star, Maureen McCormick, when they played brother-sister duo Marcia and Greg Brady on the beloved sitcom.

The pair’s dynamic was explored by Williams, 71, and producer Lloyd Schwartz, in The CW’s new docuseries, “TV We Love.”

“I remember the scene, I remember the day,” Williams recalled on the second episode of the seven-part docuseries. “I remember the day Lloyd discovered that there might have been a little bit too much attraction between brother and sister.”

“Maureen McCormick is very, very attractive… so I was, you know, gravitated right to her, and it was coming out in our scenes together,” Williams added.

Lloyd, son of “The Brady Bunch” creator Sherwood Schwartz, directed a 1973 episode of the show called “Room at the Top,” where Marcia and Greg fight over who gets the attic as their own bedroom.

“There was a scene where Barry came into Maureen’s room and she’s sitting there, and he sits down on the bed next to her,” Lloyd remembered.

Williams acknowledged that he couldn’t hide his infatuation with McCormick, now 69, in the scene.

I’m sitting a little too close, leaning in a little too far,” he explained. “We finished the scene, and it was kind of like steam there. And he was right,” he continued. “It’s very hard to hide that chemistry.”

“Lloyd was on the set,” Williams continued, “and he pulled me aside and said, ‘Good scene. I just want you to keep in mind here that she is your sister.’”

Williams and McCormick were 14 and 13, respectively, when they began starring on “The Brady Bunch.” They were in their late teenage years when the series ended after five seasons in 1974.

The pair casually dated back in the day, though their relationship never evolved into something serious.

“It was sort of like on-again, off-again with Maureen and I throughout the years,” Williams recalled on an an episode of the “The Real Brady Bros” podcast earlier this year.

“There was always a little dance being played that was broken up by hiatus,” the actor added.

Williams has been married three times. He was with his first wife, Diane Martin, from 1990 to 1992, and was with his second wife, Eila Mary Matt, from 1999 to 2005. He married his third wife, Tina Mahina, in 2017.

McCormick, meanwhile, has been married to her first and only husband, Michael Cummings, since 1985.