Most of us are familiar with the classic story of Mary Poppins, but what about the nanny's life before she tended to the Banks children? While little is known about her past, it's pretty clear that Mary has been to Cherry Tree Lane before. Not only is she familiar with the town, but she's awfully friendly with the chimney sweep, Bert. Though the state of Mary and Bert's relationship has always been a little fuzzy, a popular theory has recently resurfaced ahead of Mary Poppins Returns explaining their interesting bond: Mary Poppins (played by Julie Andrews in the original and Emily Blunt in the sequel) was actually Bert's nanny when he was a kid.

In the very beginning of the film, Bert sets the story by telling the audience, "Wind's in the East/Mist coming in/like something is brewing/about to begin./Can't put me finger/on what lies...