Jennifer Aniston enjoys a sexy, well-toned body. Why did she have to get a body double for some lingerie scenes in her new film?

Some scenes in "We're the Millers" require Aniston's character to run out of a burning building while wearing only a 2-piece lingerie set. She can run naked, all right, but not out of a burning building. The 43-year-old actress probably thinks it is "better to be safe than sorry."

The body double hired to take Aniston's place to film dangerous scenes appear to be half Aniston's age. Still, it is clear that Aniston would not need a body double if her only concern was skin exposure. In fact, Aniston has been photographed on the set wearing an open top over a well-exposed bra. See photos here and here.

While Aniston is busy filming in Wilmington, fans hope the former 'Friends' sweetheart still has time to plan for her wedding to fiancée Justin Theroux.

Theroux, 41, proposed to Aniston on his birthday, August 10. A Daily Mail source said he had an "amazing birthday" because of the engagement.

"Justin Theroux had an amazing birthday on Friday, receiving an extraordinary gift when his girlfriend, Jennifer Aniston, accepted his proposal of marriage," the source said.

People magazine also quoted a source, saying a lot of people are excited over the engagement.

"Everyone is really excited for them... It's amazing to see how happy Justin makes Jen, and everyone was always hoping that he would propose," the source told People.

This would be Aniston's second marriage. She married Hollywood A-lister Brad Pitt in a grand Malibu ceremony in 2000, but they split after Pitt filmed "Mr & Mrs Smith" with Angelina Jolie in 2005.