Nobody messes with Brody Jenner's little sister.
In a new clip that has surfaced online from the next episode of "Keeping Up With the Kardashians," Jenner, 30, and his younger half sister, Kendall, 18, are at a bar in Thailand on a recent family vacation. While Jenner orders a round of drinks, his sister stands nearby.
That's when a man sitting on a barstool reaches out to grope Kendall's bottom.
"Excuse me!" the up-and-coming model exclaims in the video, quickly moving to her brother's side.
"Brody, that guy just touched my a**," she tells him. "That guy just grabbed my a**."
Her big brother reacts immediately, confronting the man.
"Did you just f***ing touch my sister?" he asks.
The guy denies it, but Brody is unwilling to let it go.
"Are you f***ing kidding me, bro?" he says, knocking the man's sunglasses off his head.
The full episode airs Sunday, Aug. 3.