The four members of McFly, Danny Jones, Tom Fletcher, Dougie Poynter and Harry Judd, began by singing their hit It's All About You before Busted's James Bourne and Matt Willis joined them on stage to sing Year 3000.
True to their promise of playing songs by both bands, the quintet then performed Busted's 2004 single Airhostess before closing with McFly's Shine a Light.
"Amazing day, amazing night and amazing fans," said 27-year-old Danny on Twitter. "I salute you x #McBusted."
"WELL WHAT A DAY!" added Matt. "Great Britain! I LOVE YOU xxx"
McBusted's performance helped Children in Need raise a record £31 million for disadvantaged children and young adults in the UK.
Friday's staggering on-the-night sum of £31,124,896 surpassed last year's total which stood at £26 million.
Also taking part in the highly anticipated show were Olympic ice skaters Jane Torvill and Christopher Dean, who went head to head in a special edition of Strictly Come Dancing.
The cast of EastEnders also got into the charity spirit, taking part in a dance-off in the soap's famous Albert Square and Ellie Goulding performed the official BBC Children in Need single How Long Will I Love You.