Karen Dotrice, born in 1955, played little Jane Banks in the Disney classic – which came out when she was only nine.
At wasn’t even her first credit: she had previously appeared in The Three Lives of Thomasina, which – funnily enough – also starred Matthew Garber, who played her brother Michael in Poppins.
Dotrice went on to star in numerous TV films and, as an adult, one more feature film.
However she retired from showbiz in 1984; making her final appearance in a pre-Broadway production of Othello in 1981.
She had plenty of work before then, though – and in 1979 she won the Evening Standard British Film Award for Best Actress, after starring in The Thirty Nine Steps.
She made a brief comeback in 2005, starring as a school teacher in the show Young Blades, set in 17th-century France.
She then also contributed to the documentary movie The Boys: The Sherman Brothers’ Story.
Now 62, Dotrice makes public appearances very rarely, but did attend the premiere of Saving Mr Banks back in 2013.
Mary Poppins is being revived in 2018 with a new movie, which focuses on Jane and Michael Banks in adulthood.
Emily Mortimer has taken over the role of Jane, while Ben Whishaw plays her brother.
Mary Poppins can be seen on UK TV on Boxing Day at 3:45pm on BBC One.