Here’s the story … of how two TV sisters are still not getting along after all these years.

“Brady Bunch” stars Maureen McCormick and Eve Plumb are still not getting along, reportedly causing the cancelation of a televised reunion planned for this week.

All the actors who played the Brady kids were slated to do an interview Wednesday on NBC’s “Today Show” — but when McCormick and Plumb found out they were going to be on the same show, the reunion fell apart, sources told RadarOnline.com in article posted this morning on their Web site.

McCormick, who played the TV family’s oldest sister Marcia Brady, revealed in a tell-all book in 2007 how she had a steamy on-set sexual relationship with Plumb, who played her younger sister Jan.

The book, titled “Here’s the Story,” shocked fans of the 1970s hit show when McCormick detailed how a small crush blossomed into a romantic and physically intimate relationship between the two “sisters.”

Sources told RadarOnline that “the bottom line is that they didn’t want to be on the same show and the appearance was canceled because of it.”

The source added that “some people blame Maureen and some people blame Eve.”

In November, Susan Olsen, who played little sister Cindy, spoke of the long-standing feud, saying she can sympathize with Plumb.

“I don’t like there to be a rift in the family. I love them both and this means whenever we get together for any project there will only be one or the other. But I do understand Eve’s point of view,” Olsen told Fox News. “She got tired of Maureen gaining attention for herself by regurgitating the tiresome and false insinuations that they had a lesbian affair.”

But another source said the feud goes back to the days when Jan’s character would whine, “Marcia, Marcia, Marcia,” each time her TV sister scored a date or made the cheerleading squad.

“But really the problems between them go back decades,” said the source who knows them. “They’ve never liked each other.

“And there have been many other events where Eve has said, ‘I’m not doing it if Maureen is doing it.’”

Last year, McCormick hoped the two could bury the hatchet.

“It’s such a drag because I loved her,” McCormick told Fox News. “I hope we can work it out.”

It’s not the first time salacious details of behind-the-scenes sex have emerged in the years since the campy classic went off the air.

In 1992, co-star Barry Williams, who played Greg Brady, wrote in his tell-all tome, “Growing Up Brady,” how he dated not only his on-screen mom, Florence Henderson, but engaged in several romps with McCormick as well.

And in 1997, McCormick hinted at a lesbian tryst between her and Plumb when she told a Los Angeles radio host about the crush she developed for Plumb while the two worked closely on the popular sitcom, which ran from 1969 to 1974.

“We had really good times together,” she playfully said at the time.

When asked if that meant the two had been “pattycake close or Ellen DeGeneres close,” McCormick coyly revealed the two had swapped spit.

“Yeah, we kissed,” she said.

Her publicist later clarified that she meant simply on the cheek.