The character’s name is taken from the short story The Marble Boy, which appears in PL Travers’s third collection of Mary Poppins stories, Mary Poppins Opens the Door, when the children find it written on the inside leaf of a book cover.
Emily Blunt will play Mary Poppins and Meryl Streep has been cast as her cousin, Topsy. Lin-Manuel Miranda will play a street lamplighter called Jack.
Firth and Blunt have previously starred together in the 2012 drama Arthur Newman.
Mary Poppins Returns is scheduled for release on Christmas Day 2018.
via theguardian.com