Co-starring roles with Cabaret star Alan Cumming and film star Robert DeNiro are in the offing at the Bay Street Theatre's Summer Gala Benefit on July 11. Well, not exactly "co-starring": the highest bidders at the benefit fantasy auction could win the chance to dance with Cumming on stage at the Broadway revival of the Kander & Ebb musical or be a walk-on in DeNiro's upcoming film Flawless.

Also on the auction block is a five-day vacation at the new Four Seasons Resort on the island of Kuda Huraa in the Maldives. A silent auction will feature such items as tickets to the taping of TV's "Spin City" and a private portrait sitting by Robby McDowell.

Film stars Alec Baldwin and Kim Basinger, who are also husband and wife, will host the Bay Street Theatre's Summer Gala Benefit. The event will be held under a tent on Long Wharf in Sag Harbor, Long Island, N.Y.

The theatre promised cocktails, a sumptuous dinner provided by Sagaponack's Loaves and Fishes, and dancing to the sounds of the Peter Duchin Orchestra. Proceeds will support the theatre's many ventures, including its mainstage productions. Tickets range from $195-$500. For information, call (516) 725 0818.

Baldwin and Basinger are Hamptons habitues. Baldwin has occasionally graced the stage, most recently in this past season's Public Theater production of Macbeth. Basinger is known primarily for her film work and won an Oscar this year for her performance as a high-priced call girl in L.A. Confidential. -- By Robert Simonson