Playbill On-Line has learned that Hayley Mills will begin previews for her role in Noel Coward's Suite in Two Keys on March 28 at Off Broadway's Lucille Lortel Theatre. The show opens April 10.

Joining Mills in the cast will be Paxton Whitehead, who will play the role that had been linked to Keir Dullea in earlier reports. "We're still in the process of casting some other parts," a production source told Playbill On- Line.

Mills' New York Theatre debut in Suite in Two Keys was originally planned for December but delayed for lack of a "suitable Off-Broadway theatre," which has now been named.

As reported earlier, Suite is being produced by Mirage Theatre Company (Miranda d'Ancona and Doris Kaufman) and StageWrite Entertainment Inc. (Todd Alan Price).

An evening of two one-act plays, Coward's Suite comprises Shadows of the Evening and A Song at Twilight. Both were originally presented in 1965 in London's West End with Noel Coward, Lilli Palmer and Irene Worth. This production coincides with the centennial of the playwright's birth. Miranda d'Ancona will direct the upcoming Off-Broadway version of "A Song at Twilight."

Production sources report that when the plays were originally performed in London in 1965, they were done under the title Noel Coward's Suite in Three Keys and included A Song At Twilight as a full length play in rep with the shorter Shadows of the Evening and Come Into the Garden Maud. On Broadway in 1974, Song and Maud were done under the title Noël Coward in Two Keys, with Hume Cronyn, Jessica Tandy and Anne Baxter.

Mills was a child film star who was seen in "Pollyanna" and "The Parent Trap." Whitehead's credits include Run For Your Wife and Artist Descending a Staircase.

Ticket prices have not been set. The Lucille Lortel Theatre is located at 121 Christopher Street. Tele-charge confirms that the show will be at the Lucille Lortel but had no other information. For updates call (212) 239-6200.

-- By Murdoch McBride