The `Promise This` hitmaker sang a sexy version of `Happy Birthday` and a chorus of Stevie Wonder`s hit `Happy Birthday` before kissing Tre Holloway on stage at the Manchester Arena and he was then presented with a giant gold birthday cake by some of his fellow backing dancers.
One audience member tweeted: "I can`t believe I saw Trezza kiss OMG, and I sang with Cheryl and 15,000 other soldiers happy birthday to Tre. (sic)"
Cheryl then splashed out a reported £15,000 on a party for the hunk, funding a free bar at lavish nightspot Circle.
A source told the Daily Star newspaper: "Cheryl booked out the most exclusive room in the club, which is the Inner Circle.
"They were drinking lots of expensive champagne and the cocktails were free-flowing all night long.
"Tre is a really good dancer and they were all doing routines together,"
Tre isn`t the only person Cheryl has shown generosity to on their birthday.
The Girls Aloud star has sent a set of One Direction dolls to Katy Perry - who she grew close to when they appeared on British programme `The Graham Norton Show` together - as an early 27th birthday gift ahead of her big day later this month.
A source told The Sun newspaper: "Cheryl`s been busy with her tour so she wanted to make sure she sent a present well in advance and let Katy know she was thinking of her.
"She knows what a big fan Katy is of the boys and how she has a major crush on all five of them so she knew Katy would love the dolls."