Lewis' Bleeding Love hit number one in 30 countries, while Cole has scored 21 hits with Girls Aloud
Girls Aloud star Cheryl Cole has unveiled her debut solo single on BBC Radio 1.
Fight For This Love is an understated, R&B-tinged pop song, quite unlike the hits she has scored with her bandmates.
Meanwhile, Leona Lewis, who won the X Factor shortly before Cole joined the show, has also revealed her new single, Happy, on Radio 1.
Written by Ryan Tedder, who was responsible for Bleeding Love, the song is a typically anthemic power ballad.
Speaking to BBC Radio 1's Fearne Cotton and Reggie Yates on Sunday, she said she was nervous about fans' reaction to the record.
"I've lived with this song for so long, and now I'm sharing it with everyone, so it's very nerve-wracking."
The 24-year-old also revealed that her second album would be called Echo.
"On the album, there's a lot of big sounds, and its an epic word, so I thought it'd fit the album," she explained.
Cole's profile has been raised following her successful stint as a judge on the X Factor.
She was on the cover of the UK edition of Vogue in February, and was named the world's sexiest woman by readers of FHM magazine in April.
Her solo single, which was premiered on the Chris Moyles breakfast show, was written by Andre Merritt, Steve Kipner and Wayne Wilkins - who have previously penned material for R&B stars such as Chris Brown, Christina Aguilera and Rihanna.
It was unveiled a week before Girls Aloud play the biggest gigs of their career, supporting Jay-Z and Coldplay at Wembley Stadium.
The two dates are the band's last commitments before taking a year off.
Cole's bandmate Nadine Coyle is also expected to release solo material during the break.
However, the group has not split - they signed a deal to record three more albums for label Polydor earlier this year.
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