Countdown’s Rachel Riley is set to waltz on to the Strictly dancefloor after becoming the latest celebrity to be confirmed for the new series.

The 27-year-old – who recently notched up her 1,000th appearance presiding over the letters and numbers in the Channel 4 show – is the third star to be officially named in the line-up.

TV personality Vanessa Feltz was revealed on Thursday to be taking part, while golfing legend Tony Jacklin was unveiled as the first male celebrity of the year on Friday’s One Show.

Rachel announced her involvement in the show via the BBC’s official Strictly blog – in a clip which saw her rearranging the letters on the Countdown board to read ‘I AM ON STRICTLY’.

The full line-up for this year’s series – which will feature 15 celebrities in total – will be revealed on The One Show on Monday night.

Other celebs rumoured to be taking part include Desperate Housewives actress Teri Hatcher, former Corrie star Natalie Gumede, rugby ace Ben Cohen, Hairy Biker chef Dave Myers, pop star Sophie Ellis-Bextor and model and WAG Abbey Clancy.

BBC Breakfast’s Susanna Reid also entered the frame on Friday amid reports she had signed up for the series, having already had a brush with the dancefloor in the 2011 Children In Need Strictly special.

This year’s launch show, in which the celebrities are paired with their partners, will be screened next Saturday, September 7, at 6.50pm.