The 66-year-old 'Believe' hitmaker was reported to be preparing to walk down the aisle in autumn this year for the third time.
However, Cher took to Twitter to set the record straight, reported Contactmusic.
"Lovelies, must clear up, Not getting married to Tim," she tweeted.
She has been dating Medvetz, 42, on and off since 2008.
Cher was married to singer Sonny Bono for 13 years until their divorce in 1975. She wed musician Gregg Allman later that year. They divorced in 1979.
