On last night's Children In Need (15 November), Tom Fletcher, Dougie Poynter, Danny Jones and Harry Jones of McFly joined James Bourne and Matt Willis of Busted on stage.
They were clearly loving every minute as they sang a mash-up of both band's songs, including 'It's All About You', 'Year 3000' and 'Air Hostess'.
Before the performance, Tom Fletcher tweeted: "The time is ticking, it's not long to go until our first ever tv performance as @mcbusted. Spread the word."
McBusted also posted a joint selfie behind the scenes of the charity telethon from their official Twitter account.
It was only earlier this week that the two bands announced they were joining forces and going on tour in 2014.
Third member of Busted, Charlie Simpson, confirmed shortly after that he will not be joining his old bandmates.
Children In Need has already raised over £31 million, surpassing last year's £26 million to mark its record total.
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