Over five decades after its first publication, A Wrinkle in Time is finally headed to the big screen for its first major adaptation. Directed by Ava DuVernay, A Wrinkle in Time offers a modern take on the novel by Madeleine L’Engle — including more inclusive casting and updated dialogue — but the iconic story remains the same, and follows misfit teen Meg Murry as she journeys through space and time, alongside her brother Charles Wallace and friend Calvin O’Keefe, on a mission to rescue her father from a mysterious evil force.

While the star-studded film includes Chris Pine, Gugu Mbatha-Raw, Zach Galifianakis, and star-in-the-making Storm Reid, the film also features three of the most powerful women in Hollywood: Reese Witherspoon, Mindy Kaling, and Oprah Winfrey as the three celestial beings guiding Meg, Charles, and Calvin through time and space.

As a trio, the celestial beings — Mrs. Whatsit, Mrs. Who, and Mrs. Which — work together to assist the kids on their mission to save Mr. Murry from the looming darkness. But individually, the three each bring something wildly different to the table, from their abilities to their roles within the universe.

Before you see A Wrinkle in Time, here’s everything you need to know about Mrs. Which:

Mrs. Which is the celestial being of all celestial beings. So old and powerful, she doesn’t even materialize as a corporeal being because she doesn’t have time for that (in the novel, she appears as a sort of glimmering light). Everything about Mrs. Which is somewhat commanding, and as the oldest of the celestial beings, she’s the definitive leader and mentor to Mrs. Who and Mrs. Whatsit.

But as the most powerful of the beings, Mrs. Which is also the least in tune with aspects of human life — with Mrs. Whatsit, the youngest and most in touch with human nature, stepping in on behalf of Meg, Charles, and Calvin. While Meg and Calvin are initially a little wary of Mrs. Which, Meg remarks in the novel that Mrs. Which is someone she feels they can inherently trust. As the three embark on the most dangerous part of their mission without the three Mrs. W’s, Mrs. Which provides them with the most profound, straightforward advice and warnings.

Naturally, a being as all-knowing and powerful as Mrs. Which needs to be played by the real-life embodiment of Mrs. Which — Oprah Winfrey.

While, definitely a lot more human and warm than Mrs. Which, Winfrey is the natural choice for the out-of-this-world being. Explaining to Entertainment Weekly how perfect the television icon was for the role, DuVernay said that while in many cases The Color Purple actress tried to disappear into roles, Oprah’s icon status worked for A Wrinkle in Time.

There is truly nobody more commanding than Oprah and we can’t wait to see her shine as Mrs. Which when A Wrinkle in Time hits theaters on March 9th.