Heroes star Hayden Panettiere had to stop her mother from selling her used underwear at auction.[Agencies]

Heroes star Hayden Panettiere has stopped her mum from selling her used underwear at auction.

Panettiere has been raising money for Save the Whales by auctioning off her belongings through her website, Panettiere's Closet.

But she was forced to put her foot down when some embarrassing items almost ended up on the site.

"You acquire a lot of stuff so I decided to put it on the website," Panettiere said.

"Mum pulled out some embarrassing stuff, but I’m like, 'Just don’t pull out my underwear’."

Panettiere plays cheerleader Claire Bennett on hit TV show Heroes.