WASHINGTON — One day after special counsel Robert Mueller concluded his lengthy investigation into possible collusion between Russia and President Donald Trump’s campaign, the president relaxed and spent his Saturday on the golf course with Kid Rock.

Rock posted a photo of himself and the president on a manicured golf course in West Palm Beach, Florida. Wearing American flag pants and a fedora, Rock smiled next to the president, who was holding a golf club and wearing a red hat emblazoned with "USA."

"Another great day on the links! Thank you to POTUS for having me and to EVERYONE at Trump International for being so wonderful," Rock posted on Twitter. "What a great man, so down to earth and so fun to be with!! KEEP AMERICA GREAT!!"

The president was spotted by camera crews earlier Saturday putting on a green at his golf resort with a person wearing bright red, white and blue slacks. Before Rock posted the photo, White House spokesman Hogan Gidley said the president golfed with three people but did not provide their names and would not say whether the group discussed the Mueller report.

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Attorney General William Barr announced Friday afternoon that Mueller had completed his investigation and handed in a comprehensive report. Trump has remained uncharacteristically quiet, even though a Justice Department official said no additional indictments would be handed down as part of the probe, meaning no charges would be filed alleging collusion between the Trump campaign and Russia.

The president has not posted to Twitter, his favorite social media website, since around the time the nation learned that Mueller had completed his probe. But when asked about the president's mood on Saturday, Gidley said "He's good."

Details of the report have not been made public but Barr has promised to provide Congress with a summary of Mueller's conclusions as early as this weekend. A department official, who was not authorized to speak publicly, said officials would not release those conclusions Saturday, leaving the nation waiting for at least one more day.

Rock is one of several music stars who has taken a high-profile stand in supporting Trump. He was invited to the White House in October to watch Trump sign the landmark Music Modernization Act, which guarantees increased and faster royalty payments for performers, songwriters and producers.

After the signing ceremony, Rock said, "Everybody knows that this music of business is a pretty dirty business. … But this is a great start to protect songwriters, producers, engineers – the unsung heroes behind many of these songs that go out there."

Turning to Trump, he added “There's a whole lot of people in this country that do give you a lot of credit for everything you’ve been doing for this country. We know that some people don’t give you as much as maybe they should sometimes."

Rock also visited the Oval Office in April 2017.