RACHEL Riley has been temporarily replaced on Countdown – by a YouTube star. The Channel 4 words and numbers show will ...

Rachel Riley will be replaced as the show's co-host by a mathematician and YouTuber while filming a new project .

Mathematician Dr Tom Crawford will stand in for Rachel Riley while she takes a short break to work on another project. Dr ...

Dr Tom Crawford’s videos of teaching equations in his underwear have helped him attract more than 200,000 subscribers ...

Countdown 's Rachel Riley will be temporarily replaced by YouTube math star, Dr Tom Crawford. It was announced that Riley, ...

Rachel Riley is set to be temporarily replaced on Countdown by mathematician Dr Tom Crawford, as she takes a brief hiatus ...

Rachel Riley is set to be temporarily replaced on Countdown by mathematician Dr Tom Crawford. The maths whizz will take a ...

Rachel Riley is set to take a brief hiatus from Countdown, with mathematician Dr Tom Crawford stepping in as her temporary ...

Rachel Riley has a stern warning for producers should they ever want her to leave Countdown. The 39-year-old is currently on a short break from the show she's been a part of since 2009 ...

Rachel Riley is set to take a break from Channel 4's Countdown and her replacement has already been confirmed. Oxford and Cambridge university mathematician Dr Tom Crawford will be stepping in ...

Rachel Riley replaced by 'brilliant mathematician' and YouTuber on Countdown - Riley is taking a short break from the Channel ...

Channel 4 has confirmed Rachel Riley will be replaced on Countdown while she takes a break, but who is the new host? Riley first took over presenting duties in 2009 from Carol Vorderman, who appeared ...