Hell hath no fury like a Beygency scorned.

Beyoncé fans — and anyone else opposed to people randomly attacking a woman's physical appearance — have good reason to be pissed at Kevin Federline. You may vaguely remember Federline as the former backup dancer who stole Britney Spears' heart back in 2004, prompting many dramatic headlines and numerous visits to convenience stores. The couple divorced in 2007, and share custody of their two sons, Sean and Jayden.

Apparently, his time with Spears made K-Fed somewhat of an expert on female pop stars, because he certainly has a lot of opinions on Beyoncé. The singer and husband Jay Z made headlines this weekend for catching Spears' show in Las Vegas, and Federline couldn't resist adding his unsolicited thoughts.

Here's his response to a Terez Owens comment that Bey was showing off some cleavage at the show, or, as the sports media site so charmingly put it, "let the boobs air out." Ugh.