Jodie Whittaker, David Walliams, Liz Carr and Ruth Jones are the participants in the latest iteration of long-running BBC genealogy show “Who Do You Think You Are?” that returns in October.

Produced by Warner Bros Television Production U.K.’s Wall to Wall Media, the two-time BAFTA-winning format follows U.K. celebrities who unravel their family histories. This edition, down to four parts from the usual eight, features actors.

Jodie Whittaker (“Doctor Who”) learns the reality behind a family myth surrounding her great uncle’s sacrifice in WWI while unearthing some uncomfortable truths about her great-great grandfather in Yorkshire. David Walliams (“Little Britain”) uncovers a relative’s traumatic experience during WWI and learns that entertaining runs in the family.

“Silent Witness” actor and activist Liz Carr investigates an ancestor’s role in an attempted murder, while “Gavin and Stacey” co-creator and star Ruth Jones unearths a family connection to the origins of the National Health Service.

Abigail Priddle, BBC commissioning editor for specialist factual, said: “We’re so excited about the return of ‘Who Do You Think You Are?’ one of our most-watched history series. Viewers have much to be excited about, too, with an amazing line-up of celebrities set to delve in their ancestries and uncover lost connections and unfamiliar histories.”

Colette Flight, executive producer for Wall to Wall, said: “’Who Do You Think You Are?’ is back with more of our best-loved celebrities discovering incredible ancestors in their family trees. In these challenging times, the stories of courage, sacrifice and resilience they uncover are all the more resonant, but there’s also plenty of humor along the way too.”

Participants on previous editions of the show have included Daniel Radcliffe, Naomie Harris, Kate Winslet, Olivia Colman, Boy George, Noel Clarke, Ruby Wax, Ian McKellen, Gary Lineker and Marianne Faithfull.