Everyone Knows Sutton Foster Can Sing. Now We Know She Can Juggle.

There’s busy, and then there’s bonkers.

Sutton Foster, one of musical theater’s most celebrated performers, had already committed to starring in a City Center production of “Once Upon a Mattress,” on top of developing concert shows for Carnegie Hall and Café Carlyle, when she was approached last fall about stepping into the lead female role in the Broadway revival of “Sweeney Todd.”

She hesitated.

“Sweeney” wanted new stars in January, the same month as the “Mattress” production. She would have to simultaneously master two scores and two stagings while building the bespoke concert shows and learning to speak with a Cockney accent. And even if, as it turned out, “Sweeney” was willing to wait until her “Mattress” run ended, she’d still have to do double duty — rehearsing “Sweeney” during the day while performing “Mattress” at night.

She said yes.

On Feb. 9, she took her first bows as Mrs. Lovett, the shamelessly resourceful pie shop owner in “Sweeney Todd,” alongside Aaron Tveit, also in his first night, as the bloodthirsty barber (the show’s title character). It was just five days after she took her final bows as Princess Winnifred the Woebegone, a coarse but determined marriage candidate in “Once Upon a Mattress,” and the applause was thunderous.

So how did she do it?

Plenty of people hold down two jobs at once. There are repertory companies in which actors perform in a rotating selection of shows. There are Broadway stars who spend offstage hours filming television shows. And 40 years ago, Cynthia Nixon, while still a teenager, spent three months performing in two Broadway plays at the same time (dashing from one theater to another and back again).

But still, learning the starring roles in two vocally and physically demanding musicals at virtually the same time is a feat. And, inevitably, Foster faced hurdles. Among them: Halfway through “Mattress” rehearsals, she came down with Covid (for a third time).