AceShowbiz - Britney Spears has overtaken Ashton Kutcher as the most popular celebrity on Twitter, the singer now has the highest amount of followers on the microblogging site. The "Just Married" star has been an outspoken fan of the forum since 2008 and was the first member to reach one million supporters.

But now the "Toxic" hitmaker has overtaken Kutcher, Spears has 4,955,768 followers compared to the actor's 4,944,221 online fans. And the singer is ecstatic about the news - in a post on the social networking site she writes, "This is really amazing! I love you all! I better get busy writing 4,947,608 thank you notes! U guys make me sooo happy (sic)."

Kutcher is adamant he's not bothered about Spears succeeding him as Twitter's top tweeter, he was left unimpressed when he was asked about her followers during a press junket for his new film "Killers". In a message on his Twitter blog, he writes, "2nd most pop Q 'What do U think about Brittney having more followers than u?' Answer: 'I don't care. Aren't u suppose 2B a movie reporter?' (sic)."