Cher Gets iHeart Icon Award But Fans Say Jennifer Hudson Tried to Upstage Her

Cher fans are on a tear after the iHeartRadio Awards Monday night, after Jennifer Hudson upstaged her during one of Cher's most famous songs.

Cher was accepting the Icon Award -- a huge honor. Before accepting, she took the stage with J-Hud to perform "Believe," and it had shades of another iconic duo -- Barbra Streisand and Donna Summer's duet, "Enough is Enough," where the two battled for top voice.

The song was great, but at the end, Jennifer belted out a huge high note to end the song. Some of Cher's fans thought it crossed the line. One user said, "Seriously, chill Jennifer, why are you trying to upstage Cher?"

Others felt Cher was gracious as she watched Jennifer belt out the ending.

BTW ... before singing "Believe," Jennifer paid tribute to Cher by singing "If I Could Turn Back Time."

Meryl Streep presented Cher with her award -- the 2 starred in "Silkwood" together back in the day.