WATCH: Obama endorses Joe Biden for president via Twitter

On Tuesday, Barack Obama has endorsed Joe Biden for president via an online video message posted to Twitter.

"I'm so proud to endorse Joe Biden for President of the United States," said Obama.

The endorsement is no surprise considering Biden served as Obama's Vice President while in office from 2009-2017. The video message is more than just a simple endorsement, it's also a moment for Obama to address America, and the world during the coronavirus pandemic. Obama speaks to why Joe Biden is the right candidate to deal with the problems that lie ahead.

"Choosing Joe Biden to be my Vice President was one of the best decisions I've ever made," said Obama in the video endorsement.

Obama takes a moment to address the progressives, to praise their political efforts before urging them to vote for Biden as well. The former president also talks about his affection for Bernie Sanders and commended his pursuit of liberal ideals.

Bernie Sanders also endorsed Biden via livestream on Monday, saying, "We need you in the White House. I will do all that I can to see that that happens, Joe."

Obama previously spoke with all the Democratic candidates back in November to offer advice and support.

"We have a field of very accomplished, very serious and passionate and smart people who have a history of public service," said Obama, speaking at a private fundraiser at the end of 2019. "Whoever emerges from the primary process, I will work my tail off to make sure they are the next president."

In November, Obama also warned the candidates not to go so far left that they alienate their voting base. "My one cautionary note is I think it is very important for all the candidates who are running at every level to pay some attention to where voters actually are," He told the candidates not to be "deluded into thinking that the resistance to certain approaches to things is simply because voters haven't heard a bold enough proposal."

Many left wing voters have felt discouraged as their particular candidates dropped out of the race, especially fans of Sanders. When Sanders dropped out, many felt like their hopes were lost, however Obama and his team believe Biden could still be their most useful option.

Obama's longtime advisor, Valerie Jarrett, said that the former president, "is uniquely positioned to galvanize the party around the nominee and increase voter turnout so that a Democrat is successful in the general election."

Jarrett stressed the importance of letting all candidates "stand on their own two feet." However, once a nominee was chosen, Obama would utilize his support of "a broad spectrum of the Democratic Party, both the progressive and moderate wings" to consolidate voters around the nominee.

Throughout his 2020 campaign trail Biden has praised Obama, even describing himself as an "Obama-Biden" Democrat, and he's referred to him as "an extraordinary man" during several speeches as well.

"I watched up close, his character, his courage, his vision," Biden said. "He was a president our children could, and did, look up to ... He was a great president."