Cameron Diaz and Jason Segel's 'Sex Tape' is selling fast. Promotional-wise that is. And now to complete their promotional stint for their upcoming movie, which is slated for a July 18 release, Cameron Diaz recently opened up to Esquire magazine about the nudity of the film and also graced the cover of its August 2014 issue.

There's always a first time for everything, and apparently for Diaz, this is the first time she is baring it all in a movie. At least that's what she said to the magazine, where she's gracing the cover with a black high-cut swimsuit.

The 41-year-old "Bad Teacher" lead star said, "It's a first for me." Then, she clarified that her co-actor also did his fair share.

"But Jason [Segel] gets naked, too. It's just a part of the role. So I did it. I mean you see everything," she revealed to the mag.

Of course, this isn't the first time that Segel bared everything on camera. He has notably done two films where he agreed to do full-frontal nudity.

His first was in the 2007 hit comedy "Forgetting Sarah Marshall" where he co-starred with Kirsten Bell.

Jason's nudity even reportedly left her mother stunned and crying. "I would like to inform you all that Jason has chosen to do full-frontal nudity, however, it is not gratuitous and is essential to the plot," Segel's mom said, according to Huffington Post.

Then, his next full-frontal display was for a Nicholas Stoller-directed comedy "The Five-Year Engagement," co-starring Emily Blunt. Unfortunately though, his effort to bare it all in the said film was futile since the scene didn't make it to the final cut.

Meanwhile, Diaz dished that somehow she has gained the right amount of confidence to bare it all now that she's 41.

"I like being 41. I love it. So much ... just falls away. Fear, mostly. It's the best age," the "Charlie's Angels" alum said.

"That's when a woman knows how to work things, or she doesn't care about that anymore. You just stop being afraid. You don't worry about what men think. You just don't worry that time registers anything awful," she added.

Apart from the naked scenes, Cameron Diaz also shed light on the childbirth scene in 'Sex Tape.'

"I found myself in a room in the middle of nowhere Massachusetts at 11:00 at night doing a childbirth scene, and everybody's screaming at one another -- Jason, the cameramen, the director," the actress revealed to Esquire.

And me acting like I'm trying to push a basketball out of my vajoon. Crazy shit, right? And the thing is, I always take a moment to say, 'We're lucky. This is a great job. A fun job,'" she continued.

Now, on the issue whether she wants to have kids of her own, Diaz, who is currently linked to Good Charlotte's Benji Madden, gushed, "It's so much more work to have children. To have lives besides your own that you are responsible for - I didn't take that on. That did make things easier for me. A baby - that's all day, every day for 18 years."