Brody Jenner's got his sister's back.
In this clip from Sunday's all-new Keeping Up With the Kardashians, Brody, 30, defends his half-sister Kendall Jenner, 18, when a man gropes her at a bar during the family's vacation in Thailand.
After the man is seen touching Kendall, the model quickly moves away from him, with a shocked "Excuse me!" before quickly informing Brody of the situation.
Not surprisingly, the former Hills star was having none of it.
"Did you just f**king touch my sister?" he confronts him.
… And things quickly escalate from there when Brody smacks the sunglasses off his head.
Watch the video to see the tense confrontation go down.
Keeping Up With the Kardashians airs Sunday, August 3 on E!