The outspoken presenter appeared on This Morning on Monday to promote his new book, Wake Up.
Piers chatted to hosts Holly Willoughby and Phillip Schofield about his latest project and conversation quickly turned to the upcoming US election.
President Trump had previously unfollowed Piers on Twitter after the GMB star slammed his handling of the coronavirus crisis.
However, it seems that the two have buried the hatchet as they shared a lengthy phone call recently.
Speaking to Holly and Phil, Piers said: "He rang me out of the blue last weekend. We had a half hour conversation about everything.
"He knows how critical I have been of him."
Phillip, 58, asked: "Why did he call you?"
"He was appearing on an American breakfast show and I called him out because he unfollowed me on Twitter," Piers replied.
Holly asked: "Did he follow you back?"
Piers replied: "No, but he did plug my book. So thank you, Donald. I still consider him to be a friend.
"When he's private Trump can very charming and fun. He can be a different character in public. "
Piers criticised Trump's handling of the coronavirus crisis in his Daily Mail column earlier this year.
The former newspaper editor penned: "President Trump’s bats**t crazy coronavirus 'cure' theories are not just shockingly senseless and stupid – they’re going to kill people."
After Trump unfollowed him on Twitter, Piers tweeted: "UPDATE: President @realDonaldTrump has unfollowed me on Twitter, hours after I wrote this @DailyMail column."
Piers also tweeted: "President Trump’s defence for floating bats**t crazy claims that injecting bleach can kill #coronavirus is that he was being “sarcastic”.
He added: "FFS @realDonaldTrump – this is not a joke. 50,000 Americans are dead & many more will die. Stop this nonsense & get serious."
Piers claimed in a recent Daily Mail column that Trump had won the final presidential debate with former Vice-President Joe Biden.
The Life Stories star wrote: "His performance has given him an unexpected new springboard to salvage a shock victory from the jaws of apparently inevitable defeat."
"Donald Trump won last night’s debate. Not by beating Joe Biden… but by beating himself. And in doing so, he may just have blown this race back open again."
Piers and his Good Morning Britain co-star Susanna Reid will be covering the US election on the ITV breakfast this week.
The US presidential election is due on November 3, 2020