U.S. President Barack Obama may have tipped the scales further towards Democratic Presidential candidate Hillary Clinton with his speech on Wednesday night during the third day of the Democratic National Convention (DNC) in Philadelphia.

Obama, who took to the stage to cheers of "four more years" said, "There has never been a man or woman, not me, not Bill, more qualified than Hillary to serve as U.S. president." Clinton joined Obama on the stage in her first appearance since the convention began, as is custom.

The DNC that came with great star power rallied behind Clinton. From Michelle Obama and Bernie Sanders to Hollywood star Meryl Streep, everyone spoke on behalf of the Democratic nominee.

"12 years ago tonight, I addressed the democratic convention for the first time, I was filled with faith in America...I am even more optimistic about the future of America than ever before...America I know is decent, generous and full of optimism and courage," said Obama.

His speech during the convention extolled Clinton as much as it was a scathing attack against Trump. He said that Hillary was not a quitter, no matter how much she was knocked down.

"Donald Trump calls U.S. military a disaster. He doesn't know men and women who make up strongest fighting force in the world," he said.

He took the attack further saying, "Does anyone really believe that a guy who's spent his 70 years on this Earth showing no regard for working people is suddenly going to be your champion?"

He critiqued Trump's pessimistic view of America, and the fear-mongering and divisive politics he has been playing at.

"Trump is not really a plans guys, not really a facts guy... our (America's) greatness does not depend on Donald Trump," the US President said.

He urged the audience and viewers to do for Hillary what they did for him eight years ago.

Former U.S. president and Hillary Clinton's husband Bill Clinton reportedly had tears in his eyes when Hillary joined Obama on the stage.