Sir Trevor McDonald and Baroness Floella Benjamin are among the famous faces who will guest host Countdown next month as the show marks its 40th anniversary.

The quiz show was the first programme aired on Channel 4 when the broadcaster launched in November 1982 and remains the channel’s longest-running instalment.

To celebrate the milestone, four broadcasters will each take on a weeklong hosting stint alongside resident lexicographer Susie Dent and mathematician Rachel Riley.

Baroness Floella will be up first for the shows running from October 31 to November 4 with TV judge Rob Rinder joining Dent as the guest in dictionary corner.

She will be followed by celebrity vicar and Radio 4 presenter Reverend Richard Coles the week after from November 7 to 11.

Meanwhile, Channel 5 news presenter and former BBC Breakfast host Dan Walker will take over from Rinder in dictionary corner.

Sir Trevor will return to host the show having previously presented the game show in September 2021 as part of Channel 4’s Black To Front project which saw the broadcaster hosting a day of flagship shows with black talent and contributors at the forefront.

The veteran journalist’s upcoming stint will take place from November 14 to 18 with mathematician and University Challenge star Bobby Seagull assisting Dent.

To close out the month of special programming, broadcaster Moira Stuart will host from November 21 to November 25 with actor Christopher Biggins stationed in dictionary corner.

Jo Street, head of daytime and features at Channel 4, said: “We are absolutely thrilled to be welcoming these national treasures to the Countdown hotseat to mark this 40th anniversary milestone and are equally delighted to have enticed the remarkable Sir Trevor McDonald back to Salford.

“Countdown is a much loved institution and we couldn’t imagine Channel 4 without it. Here’s to the next 40!”

Peter Gwyn, executive producer of Countdown for Lifted Entertainment, added: “It has been a sheer pleasure working with these iconic figures to celebrate Countdown’s anniversary.

“This birthday means so much to all of us who love the programme, and we can’t wait for viewers to see our month-long series of very special shows.”

On November 2, 40 years to the day that Channel 4 started broadcasting, the broadcaster’s first continuity announcer and the man who introduced the first episode of Countdown, Paul Coia, will return to introduce the show once again.

To mark the anniversary, the broadcaster will also air a roster of programmes as part of their Truth and Dare season.

Alongside its Truth and Dare Season, Channel 4 is marking 40 years of broadcasting with a special month-long run of its longest running show, Countdown.

The programme line-up includes a satirical musical about the Duke of York and a revival of the comedy TV show Friday Night Live.

Countdown airs on Channel 4 on weekdays at 2.10pm.