President Obama formally endorsed Hillary Clinton for president Thursday, her campaign announced. The endorsement came right after after the president met with her primary rival, Sen. Bernie Sanders, at the White House.

“I don’t think there’s ever been someone so qualified to hold this office,” Obama said in a video released by Clinton’s team. “She’s got the courage, the compassion and the heart to get the job done.”

The two will campaign together in Green Bay, Wisc., Wednesday.

The president, whose national approval rating hovers around 50 percent, will be a key ally for Clinton going into the general election. Presumptive GOP nominee Donald Trump, as of now, has no former presidents campaigning for him, as both former Bush presidents have indicated they will stay out of the race. Trump tweeted in response Thursday afternoon: “Obama just endorsed Crooked Hillary. He wants four more years of Obama—but nobody else does!” (Clinton replied “delete your account.”)

Clinton told NPR she’s “thrilled” Obama endorsed her. “We started off as fierce competitors. We’ve ended up as true friends,” she said.

Obama has been eager to campaign openly for Clinton against Trump, but wanted to remain neutral during the Democratic primary. “I want us to run scared the whole time,” Obama told a group of donors last week in Miami, according to the New York Times. Obama shot the video Tuesday, after several news outlets had already declared Clinton the presumptive nominee.

In his endorsement, Obama congratulated Sanders on running a “great campaign” and said he believed the primary “will make the Democratic party stronger.”

Clinton gained enough pledged and unpledged delegates to become the nominee this week, but Sanders has said he will campaign at least until Washington, D.C., votes Tuesday — the final election of the primary. Sanders is under pressure to concede ahead of next month’s Democratic convention.