Jennifer Lopez: First Video Inside Las Vegas Show ... No Lip Sync, No Problems

J. Lo launched her Las Vegas residency with a preview show for family and friends that went off without a single hitch.

Jennifer ran through her "All I Have" show at Planet Hollywood Monday night, and even though the front row was loaded with familiar faces -- like BFF Leah Remini, her mom and kids -- she nailed the routine.

Video from the VIP gig shows J. Lo hitting her marks (like a Fly Girl should) -- and, apparently, really singing instead of lip syncing.

Jen's performing on Britney Spears' off days in the same theater, and shows for the public begin Wednesday night.