President Donald Trump says he's "very disappointed" with Elon Musk after he slammed the Republican tax bill and told reporters the tech billionaire who recently left his administration has "Trump Derangement Syndrome."

As President Donald Trump sat in the Oval Office on Thursday with German Chancellor Friedrich Merz, he lamented his soured relationship with Elon Musk, his adviser-turned-social media antagonist.

Trump said he was “very disappointed” with Musk after the billionaire former backer lambasted the president’s signature bill of tax cuts and spending plans.

Trump suggested Musk, who left the government last month after spearheading the tumultuous Department of Government Efficiency, misses being in the White House and has “Trump derangement syndrome.”

“He hasn’t said bad about me personally, but I’m sure that will be next,” Trump said. “But I’m very disappointed in Elon. I’ve helped Elon a lot.”

Observers had long wondered if the friendship between the two brash billionaires known for lobbing insults online would flame out in spectacular fashion. It did, in less than a year.

“Look, Elon and I had a great relationship. I don’t know if we will anymore,” Trump said.

He said that he had helped Musk a lot and brushed aside the billionaire's efforts to get him elected last year, claiming that he would have won closely contested Pennsylvania even without Musk's help, which included spending at least $250 million supporting his campaign.

The Republican president's comments came as Musk has continued a storm of social media posts attacking Trump’s “Big Beautiful Bill” and warning it will increase the federal deficit. Musk has called Trump’s big tax break bill a “disgusting abomination.”

As Trump spoke to reporters at the White House on Thursday, Musk was watching.

“False,” he fired back on his social media platform as the president continued speaking. “This bill was never shown to me even once and was passed in the dead of night so fast that almost no one in Congress could even read it!”

Trump said Musk, the CEO and founder of Tesla, “only developed a problem” with the bill because it rolls back tax credits for electric vehicles.

“Whatever,” Musk snapped back in a post on X responding to a video clip of the moment.

He went on and said Trump could keep the cuts but should “ditch the MOUNTAIN of DISGUSTING PORK in the bill.”