Estranged KISS guitarist Ace Frehley has issued former bandmate Paul Stanley an ultimatum, offering him seven days to issue a formal apology over a recent insulting remark, or he will spill "dirt" on him and Gene Simmons. He noted this trove of documents he possesses would ruin the careers of both active KISS members.

What did Paul Stanley says that has Ace upset?

In an interview on The Howard Stern Show earlier this month (March), KISS announced the final show of their End of the Road farewell tour, and touched on a variety of other KISS-related topics. Stern asked why classic members Frehley and drummer Peter Criss didn't partake in KISS' performance at their induction into the Rock and Roll Hall of Fame, and Stanley replied with a dig at his ex-bandmates.

"[The Rock Hall organizers] were demanding, quite honestly, that we play with the two original guys, Peter and Ace, and at this point, that would be demeaning to the [current KISS] band, and also would give some people confusion. Because if you saw people on stage who looked like KISS but sounded like that, maybe we should be called PISS," the Starchild contended.

It's hardly the first time he's taken shots at either Frehley or Criss, which has repeatedly angered Frehley.

READ MORE: Ace Frehley Takes a Shot at KISS for Using Backing Vocal Tapes

How did Ace respond?

Now, in an appearance on Trunk Nation With Eddie Trunk on SiriusXM, Frehley appears to have had enough, ready to go live with what he says is a "120-page manuscript" he wrote after finishing his book if certain demands of his are not met.

"I'm going to make a statement to Paul Stanley right now. I'm telling you that I want a formal apology for what you said, and a retraction and an apology within seven days," he tells Trunk (transcription via Blabbermouth), "And if I don't get that within seven days I'm coming back on Ed Trunk's show – if you'll have me, Ed – and I'm going to tell some dirt that nobody knows about Paul and Gene, that I've always kept to myself because I'm the kind of guy who doesn't talk about this. I like to talk about positive stuff."

Frehley mentions books released by Stanley and Simmons, alleging, "A lot of times those guys are just throwing people under the bus," later making note of the aforementioned manuscript.

"My attorney has it in a safety deposit box. God forbid anything happens to me, my attorney is instructed to release it to the New York Times, Rolling Stone, everybody. So they can't intimidate me with trying to hurt me or saying 'you better not say anything about me live on the radio,' because then they're totally screwed. Their careers will be ruined," he charges.

"Those guys aren't squeaky clean," he adds, teasing some of the manuscript's contents, "You know how many lawsuits girls have had against Gene?"

Trunk also made it clear on social media that all members of KISS past and present are welcome to come on his show. The host made light of Frehley's comments about Simmons' $2,000 The Vault box set, dubbing it a "silly safe."

KISS' final show of their farewell tour will be held on Dec. 2 at Madison Square Garden in New York City. See all of their upcoming dates here and, for tickets, head to this location.

25 Nastiest Rock Feuds

More From KLAQ El Paso