President Obama, whose approval ratings neared a record high of 56% yesterday, said he had been asked recently whether the hope and optimism from his 2008 campaign remained.
"The answer's yes.. and that's because of you. In the letters you've written me, in the tears you've shed for a lost loved one, I've seen again and again your goodness and your strength and your heart," he said.
Lady Gaga appeared at Mrs Clinton's final rally of the campaign in North Carolina, while Madonna also performed a surprise, free concert for the Democrat in New York's Washington Square Park last night.
Mr Trump appeared in Manchester, New Hampshire, alongside his family.
“I am asking for the votes of all Americans, Democrats, Republicans, independents,” Mr. Trump said, “who are so desperately in need of change.”
He repeated his assertion that it was "a rigged, rigged system”.
“And now it’s up to the American people to deliver the justice that we deserve at the ballot box tomorrow,” he said, referencing the decision by the FBI on Sunday night to announce that no criminal charges would be brought against Clinton over her use of a private email server.
The billionaire businessman said that if he loses today, he "will consider [his campaign] the single greatest waste of time, energy and money".
What will Trump do if he wins? — Good question. Allah Knows!