Cameron Diaz admits she has good butt-to-crack ratio

Los Angeles - Cameron Diaz thinks she's got a good "ratio" between her butt and butt crack.

The 41-year-old starlet admits she's not shy about showing off her booty on the big screen and was pleasantly surprised by her proportionate bottom when she watched her raunchy new movie Sex Tape.

Appearing on Chelsea Lately last on Thursday night, Cameron said: "I don't consider it nudity - it's just my butt. You've seen my butt, I wear really small bikinis and small pants, so at some point, if you've seen pictures of me, you have either seen the top of my butt or the bottom of my butt.

"Now you get to see it together, so you get to see the middle of my butt - the middle crack ... you get to see how it connects.

"You get to see the actual butt crack-to-butt ratio. I've never actually seen it from that perspective because I'm in front of it so I got to see it for the first time and I was like, 'Oh, not a bad ratio!'"

The blonde beauty stars opposite How I Met Your Mother star Jason Segel in the new comedy about a couple looking to spice up their love life by making a home made blue movie and Cameron says the steamy scenes weren't meant to be sexy.

She explained: "It wasn't a vanity project ... most of the stuff we are doing is really embarrassing and unattractive, that's why our characters wanted it to be a tape that we didn't want people to see.

"It's not like it's really hot camera angles and these two people are like, 'Go ahead, take a look.'

"It's like, 'Please, nobody ever see what we just did together.'"