Mamma Mia 3s biggest challenge is all about Meryl Streeps character, Donna Sheridan, but this problem was already solved in the second movie, Mamma Mia! Here We Go Again. Its not uncommon for successful musicals to make the jump from the stage to the big screen, and among the most beloved ones is Mamma Mia!. In 2008, the jukebox musical Mamma Mia!, written by Catherine Johnson and based on songs by legendary Swedish group ABBA, was adapted into a film, with Phyllida Lloyd as director and Johnson in charge of the script.

https://screenrant.com/mamma-mia-3-meryl-streep-donna-problem-solved-flashbacks/