Who Do You Think You Are? is a British genealogy documentary series that has aired on the BBC since 2004, in which celebrity participants trace their family history. It is made by the production company Wall to Wall. The programme has regularly attracted an audience of more than 6 million viewers. More than ten international adaptations of the programme have been produced.

Mark Strong is a British actor best known for his film roles such as Prince Septimus in Stardust (2007), Archibald in RocknRolla (2008), Lord Henry Blackwood in Sherlock Holmes (2009), Frank D'Amico in Kick-Ass (2010), Jim Prideaux in Tinker Tailor Soldier Spy (2011), Sinestro in Green Lantern (2011), George in Zero Dark Thirty (2012), Major General Stewart Menzies in The Imitation Game (2014), Merlin in Kingsman: The Secret Service (2014) and Kingsman: The Golden Circle (2017), Dr. Thaddeus Sivana in Shazam! (2019) and Shazam! Fury of the Gods (2023), and John in Cruella (2021).