Imad Handi, 39, alleged that Gest, known for appearing on I'm A Celebrity..Get Me Out Of Here in Britain, paid a gun man about $25,000 to murder John in 2003.
But Handi claimed he'd managed to talk Gest out of the idea of killing the Candle in the Wind singer.
In the explosive interview, Handi alleged that Gest had gotten angry over a supposed comment John had made which insinuated David was gay during his marriage to Liza Minnelli.
John, now 70, had reportedly joked that he wanted to buy Liza a "heterosexual husband" as a wedding present to her and David, following their marriage in 2002.
As Radar readers know, Minnelli has a love for gay men. Husband Peter Allen came out as gay and Gest was rumored to be.
But former security guard Handi, speaking to The Sun almost a year after Gest died on April 12, 2016 at age 62, has alleged that John's comment caused Gest to hit the roof and want to kill the famed British pop star.
"'David flew into a rage and yelled, 'I'm going to kill that mother******. He's a dead man,' " Handi contended.
He added, "I think he was so angry because Elton rumbled who he really was."
The bodyguard said the alleged "hit" was scheduled for one of John's concerts in California on January 17, 2003.
But Handi claimed he talked his friend Gest out of his act of revenge so nothing ever happened.
Gest, who also appeared in England's Celebrity Big Brother, was married to Minnelli until 2007.
In Handi's interview this weekend, the bodyguard alleged Gest had a bad cocaine habit.
Meanwhile, as Radar has reported, sources have said Minnelli, now 71, has fallen in love with a gay male piano player.
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