Jenny McCarthy is officially a cougar.

The former "Singled Out" star turns 40 today -- but last night she celebrated a few hours early with a big party in Las Vegas!

"Being that I'm 40, I'm dressing as a cougar, so paging all young boys 2 play," Jenny tweeted before debuting her very revealing Halloween costume on the red carpet.

Hard to believe it's been 17 years since Jenny made her TV debut on the MTV dating show.

"To make u feel old, I was 23 when I did singled out. Talk about scary!", McCarthy added.

Jenny started her career posing in Playboy in 1993 and later became Playmate of the Year. She stripped for the magazine again this year.

Jenny definitely still looks great -- see how some other famous former Playmates have aged in the gallery below:


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