Ellen DeGeneres has emotionally farewelled U.S. President Barack Obama on her talk show, personally thanking him for the legacy of equality he leaves behind.

The President's doggedness towards legalizing same-sex marriage profoundly changed the 58-year-old entertainer's life, allowing her August 2008 marriage to longterm partner Portia De Rossi to be recognized nationwide.

"I want to personally thank him for changing my life," DeGeneres said. "I am a legally married woman because of him, and so is my wife."

"His courage and compassion created equality for everyone. He moved us forward and made more happen in the past eight years than I ever dreamed possible. I love him. I love Michelle."

While Obama only supported same-sex civil unions when he ran for office in 2008, his perspective shifted during his tenure. In his first years, he was a vocal opponent to Proposition 8, a constitutional change that would have rendered same-sex marriages in California—including Degeneres and Rossi's—meaningless.

By May 2012, Obama became the first U.S. President in history to throw his weight behind true marriage equality, eventually achieving legalization some three years later.

"For me, personally, it is important for me to go ahead and affirm that I think same sex couples should be able to get married," he said in 2012.

Both the President and First Lady Michelle Obama were close friends of the Ellen show during their eight years in power, each appearing in numerous segments on the daytime program.

In November 2016, Obama awarded DeGeneres with the highest honor a U.S. civilian can receive—the Presidential Medal of Freedom.

"It's easy to forget now just how much courage was required for Ellen to come out on the most public of stages 20 years ago," Obama said, adding that DeGeneres was instrumental in "pushing the country in the direction of justice".

To wrap up her five-minute long video tribute to the Obamas, DeGeneres said: "Thank you for everything President Obama and First Lady Michelle. We will miss you so much."