Klum trick or treating for UNICEF

Supermodel Heidi Klum is preparing to spook kids this Halloween after signing up as the UNICEF Trick or Treat Ambassador.

The blonde beauty and mum-of-four is fronting the United Nations Children's Fund's annual campaign, which encourages American kids to make a difference to the lives of youngsters in poorer countries.

Klum is urging her fans to log on to trickortreatforunicef.org to plan their Halloween parties, share Trick or Treat for UNICEF stories, and create virtual costumes.

She says, "I am excited to become part of a campaign that has such a special place in so many people's hearts.

"As a mom, I want my children to have everything they need to be safe, healthy and happy. I'm amazed at the work UNICEF does to provide vital support for children around the world - from education to nutrition, health care to clean water - in dire emergencies and all year round."