WASHINGTON – Tech mogul Elon Musk briefly joined the president-elect Donald TrumpUkraine had a telephone conversation with Ukrainian President Volodymyr Zelensky on Wednesday, according to a source close to the matter.

Musk, who campaigned for Trump in the final weeks of the 2024 race, was not expected to be on the call but entered the room and greeted Zelensky, according to the source. He did not participate in a substantive conversation between the two leaders, the source said.

Neither Zelensky nor Trump had previously revealed that Musk was on the call. Axios first reported his participation, which was confirmed by other media.

Trump transition team officials declined requests for comment Friday. Neither Musk nor the Ukrainian Embassy in Washington, D.C., immediately responded to requests for comment.

Zelensky on Wednesday called his meeting with Trump “excellent.”

“We agreed to maintain close dialogue and advance our cooperation,” Zelensky continued in an article on X. “Strong and steadfast American leadership is vital for the world and for a just peace.”

Trump has previously claimed that he could “fix” the war in a day, saying that if he became president-elect, “I will do it before I even become president.” He has not developed a plan to do this.

In Trump’s only debate against Vice President Kamala Harris, Trump refused to say whether he wanted Ukraine, a U.S. ally, to win the war.

“I think it’s in the interest of the United States to end this war and bring it to a successful conclusion, right,” he said. “Negotiate a deal.”

Vice President-elect JD Vance also suggested that Ukraine should be ready to cede part of its territory to end the war.

Musk also had telephone conversations with Russian President Vladimir Putin, according to a source familiar with the matter. The conversations were first reported by The Wall Street Journal.

Near the start of the war, after the invasion of Russia, Musk helped provide internet support to Ukraine. Starlink emergency receivers played a key role in helping Ukrainians communicate. Starlink systems are a service that is part of SpaceX, which Musk owns.

But he also angered Ukrainians for suggesting the country cede part of its territory to Russia. In October 2022, it suggested that Ukraine gives in Crimea to Russia as part of a possible peace deal, drawing rebukes from Zelensky and other Ukrainian officials.