Rhys is best known as one of the faces the CBBC channel and is also an actor.
He was revealed as one of the stars taking to the floor on the BBC ballroom show on Friday’s edition of Newsround.
Rhys said in a statement that he was “buzzing” to take part.
“I have dreamt about being on this show, and I know for a fact that it is going to exceed every expectation,” he said.
“I cannot wait to experience it all: the costumes, the orchestra, even Craig’s glare! I am ready!”
Rhys joins McFly’sTom Fletcher, actor Robert Webb, presenter AJ Odudu and Great British Bake Off winner John Whaite on this year’s line-up.
Other stars who have been linked to this year’s Strictly include former rugby player and commentator Ugo Monye, presenters Maya Jama and Emma Willis, BBC Breakfast’s Louise Minchin and ex-footballer Peter Crouch, whose wife Abbey Clancy won the show in 2013.
The BBC has confirmed Strictly will return for a full-length series later this year, after its run was cut by four weeks in 2020 due to the pandemic.
However, for the second year running, it will not be taking its usual trip to Blackpool due to logistical issues presented by the on-going Covid situation.
Strictly Come Dancing returns to BBC One this autumn.