Isabel and Ruben Toledo create costumes for Broadway's 'After Midnight'

First the runway, then the Beltway — now Broadway. Fashion designer Isabel Toledo’s career has reached a new stage.

For many years, Toledo was a New York high fashion fixture before gaining global acclaim for the pale yellow outfit Michelle Obama chose for the presidential inauguration in 2009.

But in a week and a half, Toledo, 52, will go from the White House to the Great White Way when she makes her debut there, designing costumes for the jazz revue “After Midnight.”

Designing for the stage is a perfect next step, says the Cuban-born New Yorker and FIT grad who stitched together her respected independent brand over 25 years.

“Clothes are theater,” she says. “Every single day, we all dress to play a role.”

In this case, there are lots of them. She’s conjuring more than 100 costumes for dozens of characters in the song-packed show celebrating Harlem’s Cotton Club in the ’20s, ’30s and ’40s.

The revue, which previews on Oct. 18 and premieres on Nov. 3 at the Brooks Atkinson Theatre, features a rotating cast of headliners. First up is Fantasia, followed by k.d. lang — meaning Toledo’s work doesn’t wrap up when the curtain rises.

As usual, she’s working in concert with her husband, Ruben, an illustrator who’s known for his colorful and whimsical sketches. Those drawings fill the walls and tables of the couple’s sun-soaked studio in Manhattan.

That airy workspace is a long way from Memorial High School in West New York, N.J., where they met as starry-eyed kids who once managed to score free tickets to see Katharine Hepburn — Isabel’s favorite — on Broadway in “A Matter of Gravity.”

This time, Broadway came to them.

Producer Scott Sanders and director-choreographer Warren Carlyle were so enamored with Isabel’s designs that the pair stopped by their studio to make a pitch, dancing shoes included.

“They all showed up one Sunday,” says Ruben. “They presented what they were thinking. It was like a mini-musical.”

Sanders described the show as Carlyle swayed to tunes like “Between the Devil and the Deep Blue Sea” and “I’ve Got the World on a String.”

“As I watched Warren dance,” Isabel says, “I saw what I’d be doing. It was easier than having somebody describe the show and the clothes. Ruben and I said ‘Yes, we’ll do it,’ before the meeting was over.”