The one-day drive by the Missing People organisation to find lost kids marks International Missing Children's Day on Monday (25May15) and a host of celebrities have taken to to spread the stories via social media.

Welsh actor Sheen retweeted a message from the charity and added, "Today is International Missing Children's Day @missingpeople tweeting details missing child every 30mins #TheBigTweet RT the tweets to help (sic)."

Cowell tweeted, "It's that time of year again - missingpeople's #TheBigTweet. Hopefully we can reunite more missing children with their families this year."

Fry wrote, "Morning #TheBigTweet team. You're doing so well. Just marvellous to see so many people sharing @missingpeople's appeals," and Harry Potter author J.K. Rowling declared, "Today is International Missing Children's Day. Please help by RTing @missingpeople's appeals - we can help find lost children. #TheBigTweet (sic)... Please keep RTing @missingpeople's appeals, lovely followers! This works - children have been found through #TheBigTweet! (sic)."

Little Mix pop star Perrie Edwards added, "I'm supporting #TheBigTweet! @missingpeople will be tweeting details of missing children every 30 mins. RT their tweets to get involved (sic)."