Sarah Harding has judged a competition to find 'UK's Happiest Cat'.

The former Girls Aloud member - who loves her cat Marley - ''can't wait'' to announce the pretty pussy who's won the chance to star in the next billboard advert for O2 Refresh, as well as a year's supply of cat food.

Sarah, 33, purred: ''I was delighted to be asked by O2 to be on the panel. I am a huge cat-lover and am often posting pictures of my Persian cat, Marley, on Instagram and Twitter - he's a huge part of my life.

''Today, we have seen some incredibly smiley cats from all over the country and I can't wait to see the winning cat up on a billboard in London, what a great opportunity!''

The feel-good felines and their proud owners met the judges in Pineapple Dance Studios, London, where stars throughout West End history have been cast for shows including 'Cats'.

The group of cheerful cats were shortlisted after their owners submitted pictures of their felines' smiling faces through social media, beating more than 140 hopeful entries.

As well as Sarah, the judging panel included cat agent and expert, Charlotte Wilde and O2's Head of Creative Kat Ward-Smith who were critiquing each cat on how bright their eyes were, how soft their fur was, the length of their whiskers, their temperament and personality.

The winner will be revealed on 21 May, alongside their advertising debut.