Nicole Kidman Wows Critic-Heavy Audience as Lucille Ball in New Movie

Nicole Kidman has a lot of doubters over her turn as Lucille Ball in a new movie about the iconic actress -- but those folks will be silenced ... so say critics, who were blown away.

Aaron Sorkin's new flick, "Being the Ricardos," got its first screening in L.A. this weekend -- in front of a crowd of professional movie reviewers, no less -- and the consensus seems to be ... NK absolutely killed it as Lucy/Lucille ... and she may well be on her way to an Oscar.

The first reactions were mostly positive ... with folks saying Nicole captured the spirit of Lucille (both as Lucy Ricardo and the real-life Lucille Ball) down to a T -- including a spot-on impression of her voice and mannerisms, according to the people who watched it.

There were rave reviews for Javier Bardem as well -- who plays Lucy/Lucille's on-and-off screen hubby Desi Arnaz/Ricky Ricardo -- and ditto for J.K. Simmons and others who also star in the movie. Nicole, however, seems to have stood out from the rest ... which is interesting.

Frankly ... much has been made about Nicole's casting as the lead, because -- well, she doesn't really look like Lucy or Lucille very much at all ... even when she's in costume and makeup.

A lot of "I Love Lucy" fans were incensed by the decision to tap NK -- saying she doesn't even slightly resemble Lucille ... meanwhile, Debra Messing (who's considered a dead ringer for LB) is there, presumably available to take on the role many feel she was born to play.

Sorkin shut all that down in a recent interview ... defending his choice of Nicole, saying the best performances of real people don't always have to be about matching their look.