Elon Musk participated in a phone call between U.S. President-elect Donald Trump and the president of Ukraine Volodymyr Zelensky – indicating the billionaire businessman’s influence in the new administration.

According to Bloomberg and the New York Times, Musk was in the room when the call was made, according to the person familiar with the conversation. Trump put the phone on speakerphone to allow Musk to participate, said the person, who spoke on condition of anonymity.

Axios was the first media outlet to report that Musk was on Trump’s call with Zelensky. The person with knowledge of what happened described the conversation as brief and said Musk’s participation was not planned in advance, adding that Trump often likes to include those in the room when he takes calls.

Musk has supported Trump’s campaign and the newly elected president has said he will use Musk, the man behind SpaceX and Tesla Inc, for a role in his new administration that will focus on cutting spending.

Trump, before his victory, had promised to broker a deal between Zelensky and Putin to end the years-long invasion of Ukraine.