Speculation about the singer's future in the lineup began on Twitter last night, with Ewen being tipped to leave two years to the day it was announced that she had joined the group.
However, Ewen took to Twitter to quash the claims this morning, reassuring fans that she is working on the Sugababes' eighth album with bandmates Heidi Range and Amelle Berrabah.
"Wow! So who started this rumour guys??" the 23-year-old wrote. "The only place this Sugababe is going is to the studio with the girls to work on our new album!"
Rumours were further fueled after current single 'Freedom' was removed for pre-order from a number of online stores, including iTunes and Amazon.
The band have since confirmed on their Facebook page that it will be available as a free download "as a thank you to their fans" on Amazon from September 25.
Ewen joined the Sugababes following the exit of last remaining original member Keisha Buchanan in September 2009.
Last month, it was revealed that former member Mutya Buena had won the rights to use the Sugababes name on a number of limited products including stationery and gift wrap.
Watch the Sugababes' 'Freedom' video below: