Julie Andrews looks to be heading to theaters in December, but not in Disney’s Mary Poppins Returns. Aquaman producer Peter Safran told Entertainment Weekly that Andrews will voice a role in the DC superhero pic that opens December 21, two days after Mary Poppins hits theaters in a revival of a character Andrews made famous.

She will voice Karathen in Aquaman, a character described as a sea creature who can help assist Aquaman’s quest to broker a peace between Atlantis and the surface world.

“We wanted the Karathen to have the voice of a classic British actress, albeit somewhat digitally altered,” Safran told EW in a story published Friday. “And when we found out Julie was interested and available and excited to do it, casting her was a no-brainer.”

Andrews starred in 1964’s original Mary Poppins but is not involved in the reboot, which stars Emily Blunt as the magical nanny.