12:57 PM PT -- A rep for Cher reiterated her denial about the kidnapping claim to TMZ, telling us ... "Not true thanks for checking."

Cher says she had nothing to do with the alleged "kidnapping" of her adult son -- this despite the fact her daughter-in-law has claimed the whole thing was orchestrated by mom.

The singer was asked point blank about this by the New York Post, which did a new interview with her chronicling her career and legacy. During the chat, they brought up this bizarre story that surfaced last month ... courtesy of Marieangela King (aka Queenie).

In recent court docs pertaining to her ongoing divorce from Cher's son, Elijah Blue Allman, King made a startling allegation ... namely, that Cher supposedly had Elijah forcibly taken from his hotel room in late 2022 ... this while he and MK were attempting to reconcile.

Per Daily Mail, Elijah had been staying at a hotel in L.A. for several months at the time -- allegedly battling substance abuse -- when this staged abduction/intervention took place ... so says King in a declaration she made in court. She claims that, as they were talking in his room, four men stormed in and snatched Elijah against his will ... dragging him away.

King alleges that one of the men revealed to her that Elijah's mom, Cher, had actually hired them -- adding in her court paperwork, "I am currently unaware of my husband’s wellbeing or whereabouts. I am very concerned and worried about him." She also said she believed he was at a rehab facility at an undisclosed location ... without access to his phone.

Now, one month after all these revelations surfaced ... Cher is outright denying any involvement. She told the Post, "I didn’t do it, and if I did it, I wouldn’t say I did it."

She adds, "You never stop being a mom -- you go to the end, you go to the mattresses when you’re trying to save your children. But I didn’t do it. And if I did it, I wouldn’t care to tell you." Interestingly, this echoes what she told People about 2 weeks ago.

At the time, she said ... "I’m a mother. This is my job -- one way or another, to try to help my children. You do anything for your children. Whenever you can help them, you just do it because that’s what being a mother is. But it’s joy, even with heartache -- mostly, when you think of your children, you just smile and you love them, and you try to be there for them."

FWIW ... Elijah's father, Gregg Allman, died in 2017 from complications tied to liver cancer. Also, we've reached out to Cher's team for further comment -- so far, no word back.