The pals of Busted knocked Usher from the top of the singles charts and the R&B star was toppled from the album charts, by Anastacia.
McFly popped in for a webchat with Newsround on Friday, and the boys told us they'd sneaked to the shops to buy a few copies of their own single.
Looks like it worked too giving them a great start to their music career.
The only other new entry in the top 10 was at three, with Slow Jamz by Twista making their debut there.
Usher's album dropped from one to three, with rockers Guns N' Roses seeing their Greatest Hits climb one place to number two.
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