Even though she is a well-known figure, it appears that we have been misspelling Julia Roberts’ last name incorrectly all this time.

During a sit down conversation with Henry Louis Gates Jr. on an episode of PBS’s “Finding Your Roots,” which aired Jan. 11, the Oscar-winning actor discovered a centuries-old family secret.

“Wow. Is my head on straight still? Am I facing you?” the “Ticket To Paradise” star asked after learning that technically, she is not the Roberts she thought she was, thanks to an affair her paternal great-great-grandmother had with a married man after her husband passed away.

During the episode, Gates walked the actor through census data about her family. Roberts’ great-grandfather, John Roberts, was listed as being 2 years old and living with his siblings and his mother, Rhoda Suttle Roberts.

The census did not include the name of John Roberts’ supposed father: Rhoda’s husband, Willis Roberts.

That’s because Willis Roberts died in 1864, over a decade before John Roberts was born. For Gates, Willis Roberts’ years-long absence and the age of John Roberts sparked the loaded question of his paternity.

To find answers, Gates took to DNA.

Ultimately, samples provided by Roberts and a first cousin on her father’s side revealed that her ancestor’s true father was a man named Henry McDonald Mitchell Jr.

According to Gates, Mitchell lived a few miles (or, as the actor quipped, “a few short miles”) from Rhoda Suttle Roberts.

“So we’re Mitchells?” Roberts asked.

“You’re Julia Mitchell,” Gates Jr. replied. “You are not a Roberts, biologically.”

The soapy knot in Roberts’s family tree also revealed that Mitchell was married and had six other children who lived with him and his wife. Moreover, Mitchell had a mother who lived “just four households” from Rhoda’s home.

“And Sarah (Mitchell’s wife) was probably saying, ‘Oh, you’re gonna go see your mom. That’s so sweet,’” Roberts imagined of how the affair might have been able to continue.

“Nobody knew,” Roberts assumed of the people who lived in the same town at the time.

“Well, everybody near that farm knew because her husband wasn’t there, and she was still having babies,” he noted.

Roberts concluded by saying her “mind was blown” by the “fascinating” twist. And that she likes being a Roberts, even if her DNA says otherwise: “I do prefer the name Roberts.”