Jennifer Lopez -- aka Hollywood's shining proof that there is a fountain of youth out there somewhere because she clearly drinks directly from it -- is going topless in her latest movie, 'The Boy Next Door,' in her most revealing sex scene yet.

Many actors and actresses will choose to use a body double when it comes to nudity, and that's something we can totally understand. Talk about uncomfortable! But Jennifer was intent on getting it right, so she made the decision to strip down to her underwear -- without the use of a body double.

In an interview with E! News she said, "Those scenes are embarrassing. They are uncomfortable, but your job as an actor is to make it believable and this movie in particular...hinges on if that was believable, that it was enough to make this guy go insane."

Naturally, Jennifer's partner in the scene, Ryan Guzman, was uncomfortable when it came time to perform. We can't even imagine what it would be like to be in the same room with a fully-clothed Jennifer, so we don't blame Ryan for being nervous about having to do a sex scene with her. He said, "She was the one who kept me at ease. She talked me down. She said, 'We're going to do this [and] we're going to do that. Everything is going to be fun. You're going to have fun.' It was."

'The Boy Next Door' is slated for a Jan. 23 release -- are you planning on seeing it? Let us know!

See Photos of Jennifer Lopez + More Celebs Without Makeup!