Derek Hough: Vines from 'Dancing with the Stars' Rehearsals!

Derek Hough keeps it cool under his fedora while out at The Grove on Saturday afternoon (April 6) in West Hollywood, Calif.

The 27-year-old dancer has been busy in rehearsals for Dancing with the Stars with his partner, country singer Kellie Pickler!

PHOTOS: Check out the latest pics of Derek Hough

Also pictured: Mark Ballas arriving at the DWTS studios for rehearsals that same day.

Click inside to see a fun video Derek posted on his Vine of Kellie having an inch worm race…