The ex-Good Morning Britain host was responding after Trump criticised him in a statement about his upcoming interview with Piers.
Writing in The Sun, Piers referred to a heated part of the interview where the pair clashed over the results of the 2020 US presidential election.
Directly addressing Trump, he wrote: “You reiterated in your statement that I’m a fool if I truly believe those results.
“Well, I do — as do many senior Republicans from Mitch McConnell to Mike Pence — so I guess I must identify myself, by your criteria, as a fool.
“That doesn’t change my conviction that you lost the 2020 election fairly, and to date you’ve produced no hard evidence to suggest otherwise.
“Until or if you do, I politely suggest you stop perpetuating such absurd delusion which just makes you look like the world’s sorest loser and slightly bonkers.”
Trump had earlier accused Piers of sharing “fake news” after he posted an edited clip on his Twitter page of the interview that made it seem like the former president had stormed out.
The 30-second clip shows the pair arguing over Trump’s claims the 2020 election was rigged, with Morgan, 57, telling him he “hasn’t produced the hard evidence”.
In what is dubbed, “The most explosive interview of the year”, the 75-year-old is heard telling Morgan: “I don’t think you’re real” before standing up and saying “turn the camera off” as he proceeds to leave the interview.
In his statement, Trump claimed the clip was altered to make him look bad.
He said: “Piers Morgan, like the rest of the fake news media, attempted to unlawfully and deceptively edit his long and tedious interview.
“He wanted to make it look like I walked out on the interview when my time limit of 20 minutes went over by an hour.”
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The politician added: “The interview was actually very strong on the 2020 Election Fraud, with me calling him a ‘fool’ if he truly believed those results.”
In a tweet shared yesterday (April 21), Trump revealed that audio provided by his team to Breitbart News allegedly proved that Morgan and his team deceptively edited the interview to make it appear as though it was a contentious ending when it was not.
He captioned the post: “It’s totally brutal how misleading and deceptive the Morgan promo edit is.”
The full 75-minute interview will air on the launch of Piers’ new show, Piers Morgan Uncensored via TalkTV on Monday (April 25) at 8pm.