J Lo Scores First Musical Performance, After Getting Beaten by Madonna Previously

Jennifer Lopez worked for weeks on her audition for the musical film "Evita" ... only to be told she lost the part to another superstar moments after she was done trying out.

J Lo recently shared the hilarious anecdote at a post-screening Q&A for her upcoming movie musical "Kiss of the Spider Woman" ... acknowledging it was kinda crazy that she's never been in the movie genre prior.

And that's when she shared her little secret ... J Lo did go out for "Evita" in the '90s -- preparing "for weeks" -- and was even told how amazing she was right after her audition. Problem is ... she was also told in that same moment Madonna already had the role.

She can laugh it off now ... but she likely didn't think it was too damn funny at the time ... 'cause it's like, what the hell was the point of even having her come in if the starring role was already locked!?

"Evita" was based on the 1978 Tim Rice and Andrew Lloyd Webber musical ... the film being co-written by -- shockingly -- Oliver Stone. The flick was a box office and critical success ... and scored five Oscar nominations, winning best original song.