Recent 36++ Lily James Mamma Mia 2 Cast. She's best known for playing lady rose in downton abbey and lily is now starring in the darkest hourcredit: With the film's original cast returning and new additions including lily james. 2 (2018) cast and crew credits, including actors, actresses, directors, writers and more. In first images from the set of mamma mia: Lily James Mamma Mia 2 Cast - Mamma Mia 2 Cast Instagram Pictures Popsugar Celebrity In first images from the set of mamma mia: Lily james in 'mamma mia!