Mutya Buena has left pop trio Sugababes after seven years, four hit albums and a raft of awards.
Pop trio Sugababes have sold one million singles in the UK
The second founder member to quit in four years, Buena leaves at the height of the group's popularity.
But the fact that a replacement singer has already been found for their forthcoming UK tour confirms Sugababes' status as one of the UK's most efficient and successful pop acts.
Childhood friends Buena and Keisha Buchanan formed Sugababes in 1998 with third member Siobhan Donaghy, who they met at a garage party in London when they were all 13.
Within a couple of years they were signed to London Records and teamed up with producer Cameron McVey, who had worked with girl group All Saints and his partner Neneh Cherry.
Their largely self-written debut album One Touch mixed commercial garage with hip-hop and dance, impressing both pop fans and the music press with their first hit single Overload in September 2000.
Follow-up singles New Year, Run For Cover and Soul Sound failed to match its success, however, and Sugababes were dropped by London Records in 2001.
That year also saw the departure of Donaghy during a Japanese tour, when she was diagnosed with clinical depression amid reports of in-fighting between the Sugababes members.
In 2000: Mutya Buena, Keisha Buchanan and Siobhan Donaghy
Donaghy went on to release solo album Revolution In Me in 2003, produced by McVey, and performing at the Glastonbury Festival.
Sugababes could have been classed as one-hit wonders had they not replaced Donaghy with Heidi Range - a former member of pop act Atomic Kitten before they became famous.
Now signed to Universal Island, the revamped Sugababes scored their first number one hit with Freak Like Me in May 2002.
Produced by acclaimed electro artist Richard X, the single was a cover version of his own "mash-up" single which combined Adina Howard's 1995 track Freak Like Me with Tubeway Army's Are Friends Electric?
Subsequently named the best single of the year by Q magazine, Freak Like Me was followed by another chart-topper, Round Round.
The pop act's career was revived with the hit Freak Like Me in 2002
Hit second album Angels With Dirty Faces spawned a further two hits - Stronger and Shape - and in 2003 Sugababes were named best dance act at the prestigious Brit awards.
Later that year the pop act's UK success would continue with the album Three, spawning number one Hole in the Head and hits Too Lost in You, In the Middle and Caught in a Moment.
Before recording their next album the trio joined acts such as Coldplay's Chris Martin, Dido and Robbie Williams on a new chart-topping version of Band Aid's Do They Know It's Christmas?
Buena also gave birth to her first child, daughter Tahila, in March 2005.
Sugababes returned to the chart in October with Push the Button, which spent three weeks at number one and came complete with a raunchy video.
It enabled Sugababes to top both the singles and album chart simultaneously, as fourth album Taller in More Ways entered at number one.
Sugababes are due to support Take That on their reunion tour
"We've been trying to find out what we are for a long time - we're not rock, we're not R&B, we're not pop," said Buchanan on its release.
"I think we've definitely found ourselves with this album."
However, while promoting latest hit Ugly, Buena talked about how her daughter had become her main concern.
"I think it's made me calmer, to the point where I don't go out that much," the 20-year-old said. "Your mind just really concentrates on one thing."
Having helped Sugababes sell one million singles in the UK, Buena leaves as they prepare to embark on a full UK tour.
They also plan to honour their commitment to support Take That on next summer's sell-out arena tour, exposing Sugababes to an even wider audience.
"I think for our fans, the one thing Sugababes has come to stand for above all else is our consistent and unique style of music," said Buchanan.
"Obviously, it goes without saying that we will all miss Mutya, but we also knew there was still a place for bringing in somebody new who could help us carry on taking the Sugababes brand of music forward."