Doctors will celebrate its 20th anniversary this week with a special extended episode in the style of a fly-on-the-wall documentary.

The BBC soap has featured appearances from Phoebe Waller-Bridge, Jodie Comer, Eddie Redmayne, Nicholas Hoult, Emilia Clarke and Claire Foy over the years.

Phoeber Waller-Bridge as Katie Burbridge in 2009 (BBC)

The new episode, entitled A Day in the Life, will feature a dramatic brewery explosion in Letherbridge and the return of Diane Keen as Julia Parsons.

It will also feature special-guest cast members including Annette Badland, Clive Mantle, Georgia May Foote and Matt Bardock.

Jodie Comer as Kelly Lowther in 2012 (BBC)

Keen said: “The show has ultimately stood the test of time because people keep delivering excellence every day, and all those wonderful guest artists that you get to meet and work with make it an absolute joy.

“It was very exciting to be a part of the anniversary episode and I was delighted to do it. It’s been heaven and was just like going home.”

Mike Hobson, the executive producer who has worked on the show since the start, said: “Doctors has the unique ability to do something that no other continuing drama can do and we are incredibly lucky to work with such talented guest cast who work alongside our regular cast members.

“We have become known for our famous faces with literally hundreds having graced our screens over the past 20 years and we look forward to welcoming many more in the future.”

The 20th anniversary episode will air on March 26 at 1.45pm on BBC One.