By Meredith Lepore
May 15, 2015 @ 9:00 am

This week's episode of Lip Sync Battle was a family affair as Julianne Hough squared off against her older brother Derek Hough. Now, we know the pair are fierce dancers, but they also both proved to be very skilled at mouthing words to music as well. So how did it all go down?

First Derek "fake-rapped his way into America's hearts," as host LL Cool J put it, with a stellar performance to Macklemore & Ryan Lewis's "Can't Hold Us." But Julianne definitely caught the audience's attention when she brought out Meghan Trainor as she lip-synced to "All About That Bass." (Watch the battle in the video above.)

But the competition was still anyone's in Round 2. Derek fully committed to Sia's "Chandelier," complete with a blonde platinum wig. He truly gave "Mini Sia" Maddie Ziegler a run for her money! But his little sis brought down the house with her performance of The Lonely Island's "I Just Had Sex." Although the lyrics were quite scandalous, Julianne sported black hot pants and totally went for it. Watch Round 2 here:

So which Hough gets bragging rights at the next family dinner? In the end, Julianne bested her big brother and told him she'd wear her new victory belt with her jeans this month. Well, we're sure this won't be the last time these extremely talented siblings face off against each other, but it was probably their funniest matchup so far.