Jimmy, oh, Jimmy!

Actor Gavin Creel, one of the principals of the new musical, Thoroughly Modern Millie, heard what he didn't want to at the March 23 matinee: a pop in his knee.

During an Act One dance number, his knee "popped" and, at intermission, he sought a doctor's care while the company quickly prepared understudy Brandon Wardell for the role of Jimmy — the romantic love interest of the title character.

Wardell also performed Saturday night and the Sunday matinee. While Creel's injury is being assessed, Wardell will go on. A spokesman for the show said it would be known sometime March 26 what Creel's prognosis was. Sources also told Playbill On-Line that Millie dance captain Dave Eggers has also been sidelined with a broken wrist.

The new stage musical inspired by the 1967 movie musical began previews at the Marquis Theatre on Broadway March 19. The show is set to open April 18. The role of Jimmy in not necessarily dance-heavy, but in previews there is a pivotal dance moment for the character, according to observers.

Michael Mayer directs and Rob Ashford choreographs the show by Richard Morris (book), Dick Scanlan (book and lyrics) and Jeanine Tesori (music).

Thoroughly Modern Millie is presented by Michael Leavitt, Fox Theatricals and Hal Luftig, with Stewart F. Lane, James L. Nederlander, Independent Presenters Network, John York Noble, Libby Adler Mages/Mari Glick and Whoopi Goldberg.

The show plays 8 PM Tuesday-Saturday, 2 PM Wednesday and Saturday and 3 PM Sunday. Tickets range $55-$95. For tickets, call (212) 307-4100, or in-person at the Marquis Theatre box office (1535 Broadway at 46th Street).

There will be added performances on 8 PM Mondays April 8 and April 15. There are no performances Sunday April 14 or Sunday April 21.