The Saturdays singer and wife of a former Saints favourite, Frankie Bridge, is the first star to join the line-up for the new series of Strictly Come Dancing.
She said: ''I've always wanted to be a part of the show - it looks like so much fun and the costumes are just gorgeous.
''Like so many little girls, I used to take dance lessons when I was in primary school and I really love dancing but this is going to be so different from anything I have done with The Saturdays. I just can't wait to get started.''
The 25-year-old had her first taste of fame as a 12-year-old with pop group S Club Juniors and joined The Saturdays in 2007.
The girl band have racked up more than a dozen top 10 hits.
The singer will be one of 15 celebrities competing for the glitter ball trophy when the show returns to BBC1 this autumn.
Other names reported to be in the running to take part include Andy Murray's mother Judy.
The new series will be the first one without veteran host Sir Bruce Forsyth, with Tess Daly and Claudia Winkleman sharing the presenting job.