Joe Biden celebrated his 79th birthday Saturday one day after being declared "healthy" and "fit" for the presidency following an extensive but routine checkup.

The US president, who spent the day in his hometown of Wilmington, Delaware, had no public events scheduled.

That didn't stop a number of top Democrats from sending him their congratulations.

Vice President Kamala Harris wished him "a happy and joyous day" on Twitter.

House Speaker Nancy Pelosi meanwhile tweeted that, "America is grateful for your heart, your decency, your love of country, your love of people, and your principled leadership and vision to #BuildBackBetter."

Biden received an early birthday gift this week when House Democrats managed to pass his giant social welfare bill, known as Build Back Better, ushering it onward to the Senate.

Former president Barack Obama, whom Biden served as vice president, said: "Happy birthday to my friend and my brother... Thanks for giving all of us the gift of better infrastructure."

Following Biden's physical, White House physician Kevin O'Connor said the president was a "healthy, vigorous" man who was "fit to successfully execute the duties of the presidency, to include those as chief executive, head of state and commander in chief."

Biden is the oldest president in US history.