Dennis is known for presenting Family Fortunes between 1987 and 2002, as well as playing Michael Rodwell in Coronation Street and appearing in Ricky Gervais' Extras. He recently joined the Only Fools and Horses musical as Grandad.
Announcing his role as a guest host, Dennis posted on Twitter: "From 4th August until 15th I shall be hosting the iconic @C4Countdown. It is such an honour. Hope you enjoy."
Robinson hosted the iconic gameshow for just over a year, and when she announced her departure she said she had "stayed longer than [she] signed up for".
The show's previous permanent hosts have included Nick Hewer, Jeff Stelling, Des O'Connor, Des Lynam, and Richard Whiteley, who was the show's original host and was on it for 23 years until his death in 2005.
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When Murray was announced as temporary host in May, he said on Twitter that he is "like the assistant manager, given the job until the end of season", while adding that it is an "absolute honour" to host his "fave show ever".
Meanwhile, Rachel Riley wrote ahead of Murray's first show that he's a "lovely bloke" who "loves the show, the game, the contestants and the team and we all love him".
A permanent replacement for Robinson has yet to be announced, although Hewer previously told RadioTimes.com that his personal picks would include Murray or Gyles Brandreth.
Countdown airs weekdays at 2:10pm on Channel 4. If you’re looking for more to watch, check out our TV Guide or visit our Entertainment hub for more news and features.
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