You've seen plenty of celebs strip down, but never like this before. Some of the biggest A-list beauties in the game are getting involved with the "Wake Up Call" challenge, an initiative created by UNICEF [1]. The organization is raising awareness and money for children in Syria. Women like Cindy Crawford [2], Naomi Campbell [3], and Cat Deeley are posting makeup-free selfies [4] on Instagram and Twitter. Then, they nominate other stars to do the same, similar to the ALS Ice Bucket Challenge [5].

You don't have to be a celebrity to join in. Just tag your early-morning selfie with #wakeupcall and visit UNICEF's site [6] to make a donation to the cause. It's bringing a whole new (charitable) meaning to #wokeuplikethis! Get plenty of pose inspiration from these gorgeous, fresh-faced women.

Source: Instagram [7] and Twitter [8]

Lisa Rinna

Naomi Campbell

Rosie Huntington-Whiteley

Cindy Crawford

Cat Deeley

Elle Macpherson

Jemima Khan

Nigella Lawson

Daisy Lowe

Paloma Faith

Christy Turlington

Paris Hilton

Alexa Chung

Nicky Hilton