Liam Neeson on Meryl Streep Playing Aslan in Narnia: 'Nobody Liam Neeson is all for Meryl Strep taking over the role of Aslan in Greta Gerwig's upcoming "Narnia" movie — even if he's just learning about it now. Liam Neeson is all for Meryl Strep taking over the role of Aslan in Greta Gerwig's upcoming "Narnia" movie — even if he's just learning about it now.