LONDON, July 29 (Reuters) - Jodie Whittaker, the first woman to take on the lead role in sci-fi series "Doctor Who", will be leaving the television show next year, Britain"s BBC said on Thursday. The British actress has portrayed The Doctor - a shape-shifting alien Time Lord played by men since the show first appeared on British television screens in 1963 - since 2017. The 39-year-old, who described the role as "the best job I have ever had", will feature in a six-part Event Serial this autumn as well as in three specials planned for next year. Showrunner Chris Chibnall will also leave the production in 2022. "In 2017 I opened my glorious gift box of size 13 shoes. I could not have guessed the brilliant adventures, worlds and wonders I was to see in them," Whittaker said in a statement. "My heart is so full of love for this show, for the team who make it, for the fans who watch it and for what it has brought to my life ... I don"t think I"ll ever be able to express what this role has given me. I will carry the Doctor and the lessons I"ve learnt forever." Whittaker played the show"s 13th Doctor, a casting which when first announced sparked online debates. Last year, she was voted the show"s second most popular Doctor in a poll for listings magazine Radio Times. Actor David Tennant came first. Who will take over the role from Whittaker has yet to be announced.