"I thought, 'Oh, my God, I can't wait to see how fabulous I'm going to look,'" Alexander told ABC News.
Then she heard from the show's costume designer, Lyn Paolo, who used to dress Alexander when she played Eriq La Salle's sister on "ER." "She goes, 'OK, darling, what size jumpsuit do you wear?' I was like, 'Wait a minute - what?' She's like, 'Small, medium or large, what do you want? Get used to the gray,'" Alexander said with a laugh, adding, "This business will humble you."
Wardrobe aside, Alexander is thrilled to be the newest member of the cast, playing Olivia Pope's mother, Maya Lewis.
"I've been having a ball," Alexander said. "I've had a chance to meet everyone and hear them read. Everyone is from the theater, which is where I'm from. It's a joy to be amongst such a wonderful cast."
As for the "Scandal"-crazed fans, "I love that the fans really love this show. There's so much excitement as well as support. I'm just thrilled to be a part of all of it," Alexander said.
Fans will find out more about Mama Pope tonight after learning last week that she is both alive and being held captive by her husband, Rowan, played by Joe Morton, hence the jumpsuits.
"I love the world I've been dropped into," the New York City native said. "There are so many incredible storylines."
And they all spring from the mind of the show's creator, Shonda Rhimes, whose work Alexander has long admired.
"I'm such a fan of Shonda's," Alexander said. "I began my career as a dancer on Broadway. Friends kept saying, 'You got to see this young actress who used to be dancer in this movie.' I went to see Zoe Saldana in "Crossroads." Shonda wrote that. I've loved her work and vision for a long time. When she smiles at you, the sun just comes out."
In her long career, starting as a dancer for Bob Fosse on Broadway to roles in "NewsRadio," "CSI: Miami," "The Corner" and, most recently, as LaDonna Batiste-Williams on HBO's "Treme," Alexander, 56, has loved the challenge of "inhabiting such wildly different characters," she said.
But she's remaining tight-lipped about her latest one, except to say that she'll be sticking around for a while.
"Maya will be in several more episodes," Alexander said. "The plot will thicken."
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