Supporting the Peas on the European leg of their world tour, the gorgeous 26-year-old played a stunning half-hour set on Wednesday night that came close to eclipsing the main show.
Singing eight songs, including hits Parachute and 3 Words, the star also made three costume changes at the 02 Arena gig.
Starting out in camouflage gear she stripped to a nude and silver cut-out bodice and also donned a hooded white minidress.
"I can feel the energy coming from this room. It's like a dream to be up here," a beaming Cheryl told her adoring fans from the stage.
And it seems the time she's spending with Peas member will.i.am, who produced most of the tracks on her debut album 3 Words, is serving to deepen their friendship.
After the show the Fight for Your Love singer was in the Arena's VIP area sipping mojitos and dancing with the 35-year-old hip hop star, who reportedly even chatted to the singer's mum on the night.
Will.i.am has already spoken of his affection for Cheryl, who split from footballer husband Ashley Cole back in February.
"She's the most beautiful woman in the world," he said.
"I just still can’t believe Cheryl was ever cheated on. I mean, what has to be going through your head?"
Cheryl has reportedly denied any romantic relationship with the musician, but there's plenty of time for them to get better acquainted over the coming weeks.
After London, they head off for gigs in Birmingham, Manchester and mainland Europe.