Garrett Tennant biography Garrett Tennant is a London-based performer. He is currently appearing as an Ensemble in the West End production of Mamma Mia! playing at the Novello Theatre. Training: He trained at the Laine Theatre Arts, graduating with a Level 6 Diploma in Musical Theatre in 2019. Credits: Garrett played Workhouse Kid in Oliver! (2012); Jack in Finding Neverland (2012); Bruce Bogtrotter in Matilda The Musical (2013); Ensemble in Star Track (2017), Pablo in Sister Act (2017), Ensemble in The Laine Show (2018) and Jack in Into The Woods, all at the Laine Theatre Arts.