Billionaire Elon Musk joined President-elect Donald Trump's phone call with Ukrainian President Volodymyr Zelenskyy on Wednesday, multiple sources with direct knowledge of the call told ABC News.

       Musk was at Mar-a-Lago with Trump on election night as well as the day after, as previously reported by ABC News. Musk's involvement in the call further highlights his influence in the upcoming administration.

       Musk, the world's richest person, had a profound impact on Trump's campaign including a multi-billion dollar door-knocking operation, a social media megaphone and a $1 million sweepstakes for battleground voters.

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       Tesla CEO Elon Musk joins former President and Republican presidential candidate Donald Trump during a campaign rally at site of his first assassination attempt in Butler, Pa., October 5, 2024

       Jim Watson/AFP via Getty Images

       Zelenskyy wrote on social media that he had an "excellent" call with Trump, but made no mention of Musk.

       "I had an excellent call with President Trump and congratulated him on his historic landslide victory — his tremendous campaign made this result possible," Zelenskyy wrote on X.

       Ukraine's President Volodymyr Zelenskyy appears at a joint press conference with Ireland's Taoiseach Simon Harris (not pictured), amid Russia's attack on Ukraine, in Kyiv, Ukraine, Sept. 4, 2024.

       Alina Smutko/Reuters

       The call happened as Zelenskyy seeks to shore up long-term American military and financial support in its war with Russia.

       On the campaign trail, Trump has often boasted that he would be able to stop the war in Ukraine, though he has yet to provide specifics as to how, often showing a willingness to work with both sides.

       As of now, Musk is expected to return to Mar-a-Lago next week, but plans remain in flux, per sources familiar with the plans.