Enter the Guardsman, an American musical that won a contest in Denmark, will have its world premiere in London in 1997 -- under auspices of Andrew Lloyd Webber's Really Useful Group.

The piece is a stage adaptation of Ferenc Molnar's The Guardsman. Molnar's Liliom was the basis of Rodgers & Hammerstein's Carousel. Craig Bohmler wrote the music, Marion Adler did lyrics, Scott Wentworth wrote the book.

Enter the Guardsman, which won top prize in the Musical of the Year competition in Aarhus, Denmark, will premiere Sept. 17, 1997 at Donmar Warehouse, the innovative West End theatre company, which has entered into an unusual co-producing agreement with Really Useful.

Molnar's play is a backstage farce about a battling husband and wife. The jealous husband disguises himself as a dashing guardsman to test his wife's fidelity.

No director has been named for the Donmar production. According to Variety, the agreement gives Donmar 500,000 pounds to develop and produce new musicals. In return, Really Useful has first dibs on commercial transfers of the shows.

Donmar reportedly also has signed Alex James of the alternative-rock group Blur, to write an original musical set in London.

Variety quotes Donmar artistic director Sam Mendes, whose revivals of Cabaret and Company were Donmar hits, as saying, "It's time we created a reputation for new musical theater, rather than just reinventing old pieces . . . "That's the way you keep theater alive.''

Mendes was to have made his Broadway debut this season recreating his revival of Cabaret for Roundabout Theatre Company, but he insisted that it be performed in an actual cabaret setting, and a booking at a New York boit fell through. Mendes and Roundabout are still looking for a suitable setting for the 1997-98 season.