Charlotte d'Amboise got the call backstage a week ago, in the middle of ''Chicago." She was playing Roxie Hart, waiting in the wings for her scene, when a stage manager pulled her aside. Christina Applegate was hurt, he told her, and they needed her to take over ''Sweet Charity."
D'Amboise didn't panic. She headed onstage to sing one of Roxie's signature tunes, ''Nowadays." Then she stayed up all night trying to learn the part of Charity Hope Valentine, made famous in the '60s by Gwen Verdon and Shirley MacLaine. After catching an 8 a.m. flight to Chicago, where the revival was in its pre-Broadway run, d'Amboise finally realized she wasn't ready to go on. The producers sent out Applegate's understudy instead.
''That was a big relief for me," d'Amboise says.
There's no letting d'Amboise off the hook this week. Last night, after three days of rehearsals, she took over as the dance hall hostess desperately seeking Mr. Right. Her debut marked the first Boston performance of ''Sweet Charity," which plays the Colonial Theatre as part of a 10-day run before heading to Broadway.
''Sweet Charity" is a multimillion-dollar revival that begins previews on Broadway April 4 and opens officially April 21. Applegate, best known for her decade as Kelly Bundy on TV's ''Married . . . With Children," broke a bone in her foot last weekend during a performance in Chicago.
The producers have turned to a Broadway veteran who failed to get the part when she auditioned. Director Walter Bobbie, who has worked with d'Amboise before, says there's a reason d'Amboise didn't originally get the gig. And it had nothing to do with talent.
''She's one of those Broadway girls who has just worked her whole life," says Bobbie. ''When we started to do the show, we thought of Charlotte, but we couldn't raise $8 million on her name."
D'Amboise still regrets calling herself ''the replacement queen" in a 2001 story in The New York Times. She believes it typecast her even though she has opened shows and received a Tony nomination for her role in Jerome Robbins's ''Broadway." Usually she arrives after the big name has finished her run: replacing Bebe Neuwirth in ''Damn Yankees," stepping in for Ann Reinking in ''Chicago," and succeeding Karen Ziemba in ''Contact." She admits she doesn't mind being the new gal.
''I do want to open up a show, but I have to say, I love replacing," d'Amboise says. ''There's no stress of a big opening. I get a paycheck, and I get to be on Broadway. And I love working."
When d'Amboise signed on as Applegate's standby, she hoped she might get to replace her in September, when the film and TV actress's contract expires. Instead she could open the Broadway run of ''Sweet Charity."
Not that she's counting on that. Nobody has told her, for sure, who will play opening night.
''I don't want to get too excited, because you never know what's going to happen," she says from a cold dance studio near the FleetCenter after Thursday's rehearsal. ''I have to keep myself focused on the work."
The Applegate situation is delicate. Neither the actress's spokesperson nor the show's publicist will allow her to be interviewed. Applegate, who was in Boston this week to watch rehearsals, stayed out of sight when reporters were present.
Fran Weissler, who is producing ''Sweet Charity" with her husband, Barry, won't discuss the situation in the presence of the cast. She walks out of the rehearsal studio and down a hallway. Huddling in a corner, she asks an assistant to shoo away a dancer who wanders too close to talk on his cellphone.
''Charlotte is one of those triple threats that don't come around too often," Weissler says. ''She can sing, dance, and act."
But what about Applegate?
''There's no way Christina's not going to be in this show," Weissler says. ''It's just a question of when."
Applegate's mother, Nancy Priddy, did speak about the difficult injury in a phone interview this week. Priddy was in the audience in Chicago when, only about 25 minutes into the show, the lights went up. She headed backstage and saw her daughter had been hurt during an early scene. She accompanied her to the hospital.
''I've seen the X-rays, and it's not a compound fracture," Priddy says. ''It's a little bone. The doctor's saying four to six weeks, but he's also saying, 'It's up to you, Christina. Your mental attitude is very important right now.' "
The cast came off this week.
''Christina herself is going to promote Charlotte because they want people to come to the show," says Priddy. ''We don't want the show to have to close. And Charlotte is a wonderful, wonderful performer, and the show will work with her."
Bobbie turns to d'Amboise and smiles.
''Remember the last time this happened to me?" he says.
She does. It was in 1997. Two weeks before the Bobbie-directed touring production of ''Chicago" opened in Washington, D.C., d'Amboise hurt her knee. She had to miss two months as Roxie.
''I know what Christina's going through," d'Amboise says.
But she has to worry about herself for now. If Applegate hadn't been injured, the week would have been spent tinkering with the musical. Instead, on Thursday, the day before opening, d'Amboise and Denis O'Hare, who plays Charity's love interest, Oscar Linquist, work through scenes in a conference room at the Doubletree Hotel on Washington Street.
''This was going to be a boring leg and kind of antsy," O'Hare says. ''Instead I feel like I'm in a new play."
Bobbie, the legendary Broadway figure who directed the first production of ''Chicago," hasn't shaved in days. But he's upbeat, joking about how little time they've got before showtime.
''Don't worry," he shouts after a forgotten line. ''We have three or four hours."
D'Amboise knows most of the script. It's the performance she has to grow into. Bobbie cuts the actors off to point out nuances. ''Be more excited than desperate," he tells her at one point.
When d'Amboise flubs another line, she gets frustrated and begins to bang her open palm on her forehead. ''I hate this!" she yells.
Bobbie, standing over, leans in and gives her a hug.
''Don't even do that," he says. ''It's amazing what you're doing."
Later that day, d'Amboise, Bobbie, and O'Hare head across town to the dance studio, where the rest of the cast has been working with choreographer Wayne Cilento. Weissler is also in the room. They work on several acted scenes and numbers.
Bobbie runs through one of the big production numbers, ''I'm a Brass Band." On her first try, d'Amboise struggles. By the second run-through she's hitting her mark. The room fills with applause when she's done. ''We're here for you, girl!" one dancer shouts.
A lone bead of sunlight streams into the studio as the rehearsal ends. Bobbie gathers his cast.
''This has been an extraordinary two days of work," he tells them, raising his voice to a shout. ''So let's get home, get rested, and get ready to put a show on."
Geoff Edgers can be reached at firstname.lastname@example.org.