It seems the good girl cheerleader from heroes – aka Hayden Panettiere – has a naughty side.  And you’ll never guess what she did for her boyfriend’s birthday…

More pictures after the skip…

Hayden – who is only 18 – did a little striptease for her much older boyfriend Milo Ventimiglia.  She came out in her cheerleader outfit that was specially made with velcro – and stripped down to red lingerie, according to Boston.com.  Then she gyrated a little bit and gave him a kiss.

Now, if you are 31 and dating an 18 year old, would you want this ‘gift’ in front of the whole cast and crew of your show?  I don’t think so.  Milo seemed embarrassed, but Hayden didn’t.  What’s next for Hayden – Playboy?

Photos: PR Photos