Ratings-winning drama Call the Midwife is to have three more series that will keep the show on BBC One until 2020.Charlotte Moore, the BBC's director of content, said the three-series order "underlines our commitment to Britain's most popular drama series."
Three Christmas specials have also been commissioned.
A sixth series of the show, about nuns and midwives working in London's East End, has already been announced and will air in early 2017.
The drama, created by Heidi Thomas and inspired by the memoirs of former nurse Jennifer Worth, was first shown on BBC One in 2012.
A Christmas special, partly set at a missionary hospital in South Africa, will be broadcast next month.
The three new series will take the characters further into the 1960s - a time when Britain, according to Thomas, was "fizzing with change and challenge".
"There is so much rich material - medical, social and emotional - to be explored," she said in a statement.
"We have now delivered well over 100 babies on screen, and like those babies the stories keep on coming."