Julie Andrews has joined the cast of Aquaman voicing a mythical being who is integral to the plot, according to The Hollywood Reporter.
Andrews will voice Karathen, described by THR as "a creature holding the key that can assist in Arthur Curry’s (Jason Momoa) mission to create peace between Atlantis and dry land."
Karathen does not appear to be connected to any established DC Comics characters.
Interestingly, Aquaman will go head-to-head with Mary Poppins Returns at the box office - a sequel to 1964's Mary Poppins, in which Andrews famously played the title role.
Aquaman is due out in theaters December 21, 2018.