Well, this is becoming quite the unexpected family affair.
It's been common knowledge for months that Miley Cyrus and Patrick Schwarzenegger are dating ... and no, Miley did not get pregnant and dumped by Patrick.
Well, now it appears that Braison Cyrus and Christina Schwarzenegger, Miley's younger brother and Patrick's older sister, have started dating as well!
Braison, 20, is two years younger than Miley, 22. Christina, 23, is two years older than Patrick, 21. They've been an item for a few months now as well.
"They are dating and have been since a little after Patrick and Miley got official," a source dishes, noting "Both Patrick and Miley approve of the relationship."
"Miley loves her brother and she thinks it's a great match."
Patrick Schwarzenegger had a serious crush on Miley for awhile, we're told, and the singer also had big fans in Christina, 23, and their sister Katherine, 25.
"[They] were both fans before Patrick started seeing her. Christina wanted to hang with her and met her brother and thought he was hot," the source adds.
"They exchanged info and started hanging out on their own."
Miley may be thrilled, but Maria Shriver is another story.
The daughter of Eunice Kennedy Shriver - JFK and RFK's sister - now has TWO of her kids dating the kids of the guy who sang "Achy Breaky Heart."
"There is friction" between the couples and Shriver, a source said. "Maria has told Patrick the more she hears about Miley, the more she's concerned."
The former Disney star, for her part, has been trying to win Shriver's approval, noting that "She respects Maria and has been on her best behavior."
If this is her best behavior, all these Instagram photos could be a lot worse, and that tabloid report that Miley Cyrus is on drugs must be way off then.