Channeling, perhaps, the groomsmen attire of Kris Humphries -- or simply mom Kris Jenner's look -- Kardashian wore a sequined tuxedo, complete with bowtie, sitting in the audience alongside Kris Jenner, Khloe Kardashian, Kendall Jenner and Kourtney Kardashian. (Kourtney's man Scott Disick also donned prom-inspired formal wear for Rob's big night.)
Kim (licking her wounds after filing for divorce from Humphries last month) was ecstatic when her brother scored a perfect score in freestyle dance. "Did u guys see that!!!!!! All 10's in the freestyle!!!!" she tweeted. "OMG I swear the whole fam is in tears!!!!! Let's go baby! Team CherBert!"