Rouleau's other stage credits include Emmett in Legally Blonde: The Musical (U.S. national tour) and Marius in Les Miserables (Merry-Go-Round Playhouse, Finger Lakes, U.S.).
Sears' other Broadway credits include Lend Me a Tenor, Finian's Rainbow and Grease.
They join continuing cast members Alexia Khadime, Stephen Ashfield, Hugo Harold-Harrison and Chris Jarman.
The full cast will include Josh Andrews, Gabrielle Brooks, Danny Colligan, Christopher Copeland, Nicholas Corre, Brendan Cull, Tim Edwards, Keisha T Fraser, Ross Hunter, Sia Kiwa, Dan Looney, Daniel Mackinlay, David McMullan, Tania Mathurin, Abiola Ogunbiyi, Oliver Ormson, Sean Parkins, Michael Peters, Ashley Samuels, Rhys Taylor, Ricardo Coke Thomas, and Kayi Ushe.
To book tickets, contact the box office on 0844 4825110 or visit www.bookofmormonlondon.com/tickets.