Singer Ke$ha has been through a lot since she became famous, but her early life was just as tough. Her mom was a single parent, raising Kesha and her older brother, and even had a third child who was adopted by another family. Rumor has it, though her brother Lagan knew his dad (their mom Pebe was married to Hugh Moffatt), Kesha's was always a mystery.

Fans can assume that part of the reason Kesha is such a tough chick is because of her difficult childhood. At the same time, not knowing who her dad was must have been tough emotionally. The thing is, Kesha apparently has some ideas about who her father could really be.

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The story starts back when Kesha's mom was a busy artist, touring with acts like the Rolling Stones. Rosemary Patricia Sebert, or Pebe as she goes by, apparently didn't know who her daughter's father was. But fans have long speculated that Kesha's father could be any manner of famous folks, just because her mom was a successful artist who was on the road a lot.

And according to The Famous People, Kesha admitted she had no clue who her real dad was. Still, she suspects that it could possibly be Mick Jagger, of Rolling Stones fame.

As fans may know already, Mick Jagger has at least eight children that the public knows of. Of course, given his insane level of fame throughout his entire career, it does make sense that Mick might have other kids he's never met or otherwise disowned.

Plus, when Kesha was born in 1987, Jagger was with Jerry Hall, with whom he had four kids. Kesha was born right in between them, so that could be enough to suggest that if Kesha's theory is true, Mick may not have wanted to admit he had another kid out there somewhere.

Pebe's ongoing struggles during her fame, including alcohol issues, could, theoretically, contribute to keeping Kesha's true paternity under wraps.

Of course, it's all just speculation based on something Kesha sort of said earlier in her career, and there have been rumors about another potential father figure. Fans have forgotten some things about Kesha, including the fact that one man, Bob Chamberlain, says he's Kesha's father and had been in her life from the time of her birth until she was 19, Digital Spy reported.

Chamberlain says Kesha and her mom have lied, but that it's possible they did so because "Maybe someone around her thought it would be better to perpetuate those myths; I don't know."

It's an intriguing story, especially if Chamberlain truly isn't Kesha's dad. After all, since Kesha's worth $5 million these days, it makes sense that someone who isn't a superstar would claim he's related to her.

NEXT: Kesha Reveals She Once Broke Into Prince's House