NEW YORK (AP) _ ''The Gershwin Gala'' proved a true gala on Wednesday with a Milky Way of stars onstage and a constellation of chicly dressed luminaries in the audience, all celebrating the music of George and Ira Gershwin.

Performers, from a number of spheres, included Bob Dylan, Leonard Bernstein, Mikhail Baryshnikov, Bobby Short, Rosemary Clooney, Tommy Tune, Johnny Green and several opera singers.

The Brooklyn Academy of Music, where the gala was held, decided to honor the Brooklyn-born George Gershwin and his Manhattan-born, lyricist brother Ira, during March, to call attention to the Brooklyn Academy's 125th anniversary.

The concert was taped for showing by the BBC and next fall on PBS.

Mostly, the evening was an attempt to recreate the sound of Gershwin in his time. Opera soprano Erie Mills, in flapper dress and flirty with an eight-man chorus, sang ''Naughty Baby'' from 1924. Accompanying orchestration was by George Gershwin.

Bob Dylan, himself a respected songwriter, paid his tribute with ''Soon'' from 1930. He played it through on acoustic guitar and harmonica, then sang it, accompanying himself on guitar. He wore a black suit and white shirt.

Rosemary Clooney, with a voice that sounds true in pop or jazz arrangements, sang ''A Foggy Day'' from 1937.

Tommy Tune and petite Drew Barrymore, both in white tails, danced charmingly to a vintage recording of ''Fascinating Rhythm.''

In one especially interesting section, Madeline Kahn sang ''How Long Has This Been Going On?'' from 1928 in a voice that was lush, lovely and conveyed no emotion or personality, a prominent style in Gershwin's time.

She was followed by Maureen McGovern, who acts with her full-bodied voice, an approach admired in Broadway singers today. She sang ''But Not for Me,'' with the original 1930 orchestration by Robert Russell Bennet.

Then Metropolitan Opera soprano Julia Migenes, praised for both voice and vocal acting, thrillingly sang ''The Man I Love'' from 1924.

The three united to sing ''Someone To Watch over Me,'' with Miss McGovern in a duet with one then the other.

Leonard Bernstein played Gershwin's ''Prelude in C Sharp Minor'' with deep feeling.

Baryshnikov's dancing proved an opportunity for thrill missed, due to wispy choreography. The only other disappointment was the performance of the opener, ''Rhapsody in Blue,'' as orchestrated by Ferde Grofe for the Paul Whiteman Band in 1924.

Three songs from ''Porgy and Bess'' were delivered by opera singers Cynthia Haymon, Ruby Hinds and Damon Evans.

Just before the finale, Johnny Green played piano with flair and conducted his orchestra, in the 1937 arrangements, for six songs that the Gershwins wrote for movies in 1937. While Miss McGovern sang ''They All Laughed,'' Green responded to her lyrics with gracious, well-timed waves and bows.

Snappy tapper Harold Nicholas had a grand time singing then dancing to ''Slap That Bass.'' The audience loved it.

Larry Kert sang ''Swanee,'' with a female dancing chorus, to the original 1919 orchestration. Bobby Short sang ''Our Love Is Here To Stay,'' then strolled across the stage with debonair elegance. Chita Rivera and a trio, the Manhattan Rhythm Kings, sang and danced ''I Got Rhythm.''

Gregg Burge and the five Copasetics tapped through ''King of Swing'' to big applause, ending Act 1. The finale had conductor Michael Tilson Thomas asking the audience to join in singing ''Swonderful.''

That's just what ''The Gershwin Gala'' was.