WASHINGTON — President Trump undercut his attorney Rudolph W. Giuliani on Friday, and said the former New York mayor will eventually get the facts right regarding a payment to a pornographic actress who said she had an affair with Mr. Trump.

“And virtually everything said has been said incorrectly, and it’s been said wrong, or it’s been covered wrong by the press,” Mr. Trump said.

Mr. Giuliani, who joined Mr. Trump’s legal team last month, “just started a day ago,” Mr. Trump said, speaking to reporters on Friday as he left Washington to attend a National Rifle Association convention in Dallas.

“He is a great guy,” Mr. Trump said. “He’ll get his facts straight.”

It was the first time the president addressed the inconsistent narrative about the payment made by his personal lawyer, Michael D. Cohen, to the actress, Stephanie Clifford, who goes by the stage name Stormy Daniels. Mr. Trump did not offer any details on Friday to clarify the confusion, but said, “It’s actually very simple. But there has been a lot of misinformation.”