J Lo put in some serious work Thursday at the Hard Rock Hotel in Ft. Lauderdale, where she was on set with her fiance Alex Rodriguez, mega-producer DJ Khaled, rockstar Steven Van Zandt and NBA legend Kareem Abdul-Jabbar.

TMZ's obtained behind-the-scenes pics and vids showing Jennifer rocking a tight white outfit from head-to-toe, and flanked by a huge filming crew. A-Rod's wardrobe included a blue sport coat, while DJ Khaled was, of course, wearing an eye-catching, bright yellow tracksuit -- and cracking up everyone on set.

Kareem appears to be reprising his classic "Airplane" role, cause he was spotted dressed as a pilot. Roger Murdock, anyone?

As for what they're shooting? It's still a mystery ... we know J Lo was running away from a car in one scene, and they've been shooting for at least 2 days.

Jennifer's got a super-full plate. We know she's also been busy rehearsing for her co-headlining gig with Shakira in the Super Bowl Halftime Show in Miami -- but as they say, there's always room for more J Lo.

Never mind who originally said that.