While the Oscar-winner is mostly retired having not appeared in a film for over a decade, Andrews will be voicing Karathen - a mythical undersea creature who plays a poignant role in Arthur Curry's quest to unite two very opposing worlds.
It might seem like an odd choice, considering Aquaman will be going head-to-head with Disney's Mary Poppins Returns— the sequel to the 1964 film which Andrews won an Academy Award for.
However, Aquaman producer Peter Safran defends the choice.
“We wanted the Karathen to have the voice of a classic British actress, albeit somewhat digitally altered,” Safran explained. “And when we found out Julie was interested and available and excited to do it, casting her was a no-brainer.”
See the Aquaman trailer below!