In July, Kelsey De Santis became a YouTube sensation when she challenged Justin Timberlake to come as her date to the Marine Corps Ball. Timberlake accepted, and he should be arriving in National Harbor, MD., any minute now, as the 2011 Commandant's Marine Corps Birthday Ball is tonight!

Corporal De Santis spoke to Access Hollywood on Friday about her big date. When asked about her plan for the night, De Santis said her friends want her to challenge Timberlake to a dance off.

They know about my skills...I don't think he will be able to keep up with us, she said. (Us is in reference to a group of friends sharing a table at the ball.)

De Santis sounded confident and relaxed as she discussed her fairtytale night. She said she was more than happy to be wearing her uniform for most of the ball, before changing into a gown towarded the end of the evening. The 5'9 blonde is no wallflower - she recently crushed her opponent in a Mixed Marital Art event in Sterling, Va., finishing her off in less than three minutes, and barely appearing to break a sweat. She now holds the Operation Octagon XVI Featherweight title. Click here to watch a video of the fight, which finds de Santis in a revealing outfit that shows off her extremely fit, heavily tattooed body.

Justin better not be late!

Kelsey De Santis has her own Web site now, which currently features a Marine Corps Ball countdown timer. Only a few minutes left...

Watch the Access Hollywood interview here: (after the jump)