In the upcoming Paddington movie, Aunt Lucy’s mystery will be solved.

Later this year, Paddington in Peru, the third movie in the series, will be released.
The primary storyline centers on Paddington’s journey back to South America, the country of his birth, in order to locate his cherished Aunt Lucy, played by Imelda Staunton.
When asked if he could guarantee that viewers would learn Lucy’s true story, Whishaw replied, “Yes.”
He said, “You will find out,” on Sunday with Laura Kuenssberg on the news.