Katy Holmes is making a special guest appearance on US comedy How I Met You Mother - as a 'sluttty pumpkin'.

Back in his early mother-searching days, Ted Mosby (Josh Radnor) fell for a gorgeous girl dressed as a pumpkin at a Halloween party.

They failed to keep in touch, so every year he'd go to the same costume party, in the same costume, hoping she'd show up. It never happened.

Fans of How I Met Your Mother loved the story, but one major question remained: who was this so-called Slutty Pumpkin? What did she look like, and what was the attraction? It's been a mystery for years, but finally, it will be answered.

Former Dawson's Creek star Katie Holmes - now married to Tom Cruise - will guest star on a Halloween edition of the show, finally putting a face to the party girl from Ted's past.

Joey Potter would not be impressed!

How I Met Your Mother returns soon to E4