What's Up with Heidi Klum's Nose?

Uh, Heidi, you've got a little something there.

The supermodel is sporting a silly red nose these days in support of the aptly named Red Nose Day, a U.K.-based fundraiser for children's charities coming to the U.S. for the first time on Thursday, May 21, live at 8 p.m. ET on NBC.

The three-hour event features hilarious appearances from stars like Will Ferrell, Gwyneth Paltrow, Emily Blunt, John Krasinski and Jack Black and performances from Adam Levine, Blake Shelton, Pharrell Williams and many more.

Love Actually director Richard Curtis created the U.K. version of the event, which has been running for 30 years and in that time has raised more than $1 billion. The hope is that the special will have the same impact - if not greater - in the U.S.

"It's a fun way to help raise money for children and young people living in poverty," Klum tells PEOPLE. "I'm excited it's coming to the U.S. and will definitely be wearing my red nose in support!"

"It's almost like a national holiday in the U.K.," Sienna Miller adds in a statement. "It's a day of real excitement, as everyone looks forward to it and the entire country gets involved in some way."

While donations will be accepted during the telecast, anyone can buy a $1 red nose now at participating Walgreens and Duane Reade drugstores.

Leading up to the event, stars are helping in their own ways, too: Nick Cannon is hosting a 24-hour danceathon on Wednesday, May 20 (streamed live on NBC.com), and Today's Matt Lauer is doing a 225-mile bike ride from Fenway Park in Boston to the New York City Today set from Sunday, May 17, to Wednesday morning, May 21.

Red Nose Day benefits the Boys & Girls Clubs of America; charity: water; Children's Health Fund; Feeding America; Gavi, the Vaccine Alliance; the Global Fund; LIFT; National Council of La Raza; National Urban League; Oxfam America; Save the Children and United Way.

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