Duchess of Cambridge Kate Middleton and her suddenly-famous younger sister Pippa may be best friends, but that doesn't mean they're unlike most siblings.
"There is a healthy competition between the two," royal watcher Katie Nicholl tells Us. "Certainly when it comes to looks, there is a little friendly rivalry."
Kate and Pippa Middleton also squabble over "weird things," says a family source. "You'd see them fight over who had the worst headache or period pain!"
Okay. We're all about Pippa and Kate, but that's just TMI.
While Kate married Prince William, Pippa grabbed headlines for her sexy, elegant style, her chemistry with Prince Harry and later, her racy photo scandal.
"She was the sister who sparkled," Nicholl said. "She's an extrovert compared to Kate."
At boarding school, "none of the guys noticed Kate," a source says, adding that when Kate Middleton went to St. Andrews in Scotland (where she met Prince William), Pippa frequently visited to mingle with her sister's noble new pals.
"She dated a couple of the St. Andrew's lads and tried to get in with a lot of William's friends," a source says. "She wasn't sleeping around, but she flirts."
WOW! Pippa Middleton, you amaze us. Just when you think you know someone ...