Palm Beach, Florida - Five years after the death of Senator John McCain, former President Donald Trump is once again dissing him, describing his memorial as the "world's longest funeral."

In his upcoming book titled Letters To Trump, which will feature 150 personal letters to the former president during his public career, Trump reportedly includes some commentary on McCain and his 2018 funeral.

"I never warmed to him, never felt good about anybody having anything to do with John McCain and never will, even despite the fact that at their request, I gave him the world’s longest funeral, 11 days," Trump wrote.

"Much like his wars, it never ended."

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Trump even goes on to poke at John's daughter, Megan McCain.

"At the request of many of [Meghan's] representatives, I made it possible for her father to have the world's longest funeral," Trump continued, "designed and orchestrated by him, even though I was never, to put it mildly, a fan."

McCain and Trump despised each other, trading shots up until the former's death on August 25, 2018.

John McCain's funeral was held in Washington DC, and the memorial events lasted five days, not 11.

Trump was actually uninvited to the event by the family after he infamously said McCain was "not a war hero," adding he preferred "people who weren't captured" which sparked a never-ending feud between the two until McCain's death.

While serving in Vietnam, McCain's Navy plane was shot down. He was captured and held as a prisoner of war for several years.

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Upon his release in 1973, he returned home with permanent disabilities in both of his arms.

McCain, who went on to serve in politics for over 30 years, was well respected as both a veteran and politician, and incredibly popular in his state of Arizona.

Letters To Trump will be released on April 25 in bookstores everywhere, but fans will have to dish out a hefty $99 to get their hands on one.