Hayden Panettiere performed a surprise striptease on her boyfriend Milo Ventimiglia's birthday.
The 'Heroes' actress - who plays self-healing cheerleader Claire Bennett in the hit TV show - donned a special raunchy cheerleader outfit and treated her co-star, who turned 31, by gyrating in front of him, before whipping off the costume to reveal sexy red lingerie.
A source said: "Hayden gave Milo an unforgettable birthday surprise by morphing from her bouncy cheerleader character in 'Heroes' to a bump-and-grind striptease.
"She asked the wardrobe girls to make her a Velcro lined version of the outfit she wears on the show. As she sang 'Happy Birthday' to Milo in front of cast and crew during lunch she ripped off the costume to show off her sexy red lingerie. Milo's face went bright red."
Hayden finished her routine by kissing and hugging Milo as onlookers gave her a standing ovation.
Hayden, 18, who met Milo on the set of 'Heroes', recently left him heartbroken by asking her best friend to move into her new house, instead of him.