If you follow the Kardashians, you know one of the most frequently talked about rumors deals with Khloé Kardashian. Particularly, who her actual father is. Though Kris Jenner and the whole Kardashian fam assure fans that she shares the same father as her sisters, Robert Kardashian Sr., people still theorize. So who is Khloé Kardashian’s father? Here are some of the most popular guesses.

Is O.J. Simpson Khloé’s dad?

One of the most popular theories is that disgraced NFL star O.J. Simpson is KoKo’s real dad. In fact, in July of last year, it was reported that Khlo “begged” O.J. for a paternity test.

oj simpson and kris jenner

Jeffrey Felix, a prison guard for O.J., told the Daily Mail all the details. “Khloé is his favorite,” he told the outlet. “The mom Kardashian [Kris Jenner] does not talk to O.J. She’s upset with O.J. for her thinking that he killed her best friend, Nicole Brown Simpson. One day I could hear Khloé screaming in the phone. He said she was upset because she wanted him to take a paternity test because the media is all over him, to see if O.J. is her actual dad — and O.J. told her ‘no.’”

And just recently, following the announcement that the 70-year-old would be released from prison early, a source told Radar Online that Khloé is seeking the truth. “This is more than Khloe’s fears with the paternity issue,” the insider said. “It’s more to do with Kris and O.J.’s flings, what he has over the family and what Kris would do for him back when Nicole Brown was murdered.”

Is Alex Roldan Khloé’s dad?

For years it’s been speculated that Kris Jenner’s hairdresser Alex Roldan is Khloé’s father. Back in 2012, youngest Kardashian-Jenner Kylie Jenner even joked about the allegations. “First official photo of my sister and her dad! Like father like daughter!” she tweeted along with a pic of Khlo and Alex.

khloe kardashian alex roldan

Though she eventually said it was all a joke, that didn’t stop fans from freaking out. “Pleaseeee tell us if this is real or not. Haha our heads are about to explode,” one fan wrote at the time, while another added, “What the f–k!! I hope that isn't true!!”

Is Lionel Richie Khloé’s dad?

Back in 2014, a source close to Kris exclusively told In Touch that she and Grammy-winning singer Lionel Richie had an affair in the ‘80s. “They had a sexual affair — he bragged about it,” the source, who also knows Lionel, recalled. “He said he was on the outs with his wife at the time. Everyone was sleeping around with everyone else back then, and Kris was hot in those days.”

Another one of Kris’ friends, hair stylist Daniel DiCriscio, confirmed Kris was a party-loving wild child in the early ’80s. “She was a big flirt and played around. I’ve seen Kris do things that would blow people away,” Daniel told In Touch. “Lionel was a huge player back then, too.”

khloe kardashian sofia richie

Lionel’s daughter Sofia Richie, 16, happens to be the spitting image of Khloé, and Khloé has long complained about how little she resembles the Kardashians. “Sofia,” added the source, “looks like she could be Khloé’s little sister.”

Kris herself has admitted she cheated on Robert Kardashian, who died of esophageal cancer in 2003. She confessed to having “wild sex everywhere,” during her marriage, with a man later identified as soccer-player-turned-producer Todd Waterman. But sources say there were more men, the “Dancing on the Ceiling” crooner included.

Is Robert Kardashian Sr. Khloé's dad?

Of course, both Kris and Khloé assure fans that she is biologically Robert's daughter. Back in 2014, the mother-of-six talked to E! about her daughter's paternity as an effort to set the rumors to rest. “Khloé came out and she looked exactly like Robert’s mom,” she said.

khloe and robert kardashian tbt

Khlo faced some trolling after O.J. Simpson was granted his release from prison, and she quickly showed fans, when it comes to her paternity, there's no messing around. After fans tweeted at her with messages like "Daddy's home," she didn't hold back.

"People are a–holes but I don't care lol I focus on the good," she Tweeted. "They are all f-cked lol such a–holes. Hehe oh well…. I'm happy and they hatin."

Khloé has also opened up about how much her father's death affected her. On an episode of her show Revenge Body she related to a contestant who struggled with emotional eating.

"I know, to a degree, how you feel," Khloe said. "My dad died in 2003, I was 19. When it set in I was like…you spiral. And for me, my spiral was food. And I gained so much weight because I was so internally…just suppressing so many things that it was like eating me alive. And I was literally eating everything. We can't let these tragic things ruin the rest of our lives."