<Li> Christine Baranski as Tanya Chesham - Leigh, one of Donna's best friends and former bandmates in Donna and the Dynamos; a rich three - time divorcee . <Ul> <Li> Jessica Keenan Wynn as Young Tanya . </Li> </Ul> </Li> <Ul> <Li> Jessica Keenan Wynn as Young Tanya . </Li> </Ul> <Li> Jessica Keenan Wynn as Young Tanya . </Li> <Li> Julie Walters as Rosie Mulligan, one of Donna's best friends and former bandmates in Donna and the Dynamos; a fun - loving author in a relationship with Bill . <Ul> <Li> Alexa Davies as Young Rosie . </Li> </Ul> </Li>

Actors in mama mia here we go again