Barack and Michelle Obama have endorsed Kamala Harris for the Democratic presidential nomination, significantly bolstering her campaign to unify the party behind her bid for the White House against Donald Trump.

The former president and first lady announced their support in a video released on Friday, where they shared a phone call with Harris to convey their endorsement.

Barack Obama said in the video, “Michelle and I couldn’t be prouder to endorse you and to do everything we can to help you through this election and into the Oval Office.”

Michelle Obama added, “I am proud of you. This is going to be historic.”

In a statement, the Obamas emphasized, “She has the vision, the character, and the strength that this critical moment demands. There is no doubt in our mind that Kamala Harris has exactly what it takes to win this election and deliver for the American people.”

The Obamas’ endorsement is notable as they were among the last senior Democrats to support Harris recently. President Joe Biden, who served as vice president under Obama, endorsed Harris on Sunday when he exited the race and reaffirmed his support in an Oval Office address on Wednesday.

Shortly after, Bill and Hillary Clinton, as well as top Democrats in Congress such as Chuck Schumer, Hakeem Jeffries, and Nancy Pelosi, also endorsed Harris.

The Obamas had previously refrained from publicly supporting Harris, which had led to speculation about their confidence in her campaign. The Trump campaign had even suggested that some Democrats, including Obama, were waiting for a “better” candidate.

In response to the endorsement, Harris expressed her enthusiasm, saying she looked forward to “doing this with the two of you” and thanked them for their friendship.

The Harris campaign is currently evaluating potential running mates in preparation for the Democratic National Convention in Chicago next month. If she succeeds in the November election, Harris would become the first woman to occupy the Oval Office and the second Black president, following Barack Obama, who was first elected in 2008 and won a second term in 2012.

While Barack Obama had initially supported Biden publicly following the president’s challenging debate performance against Trump in June, he then refrained from further comment. This silence led many Democrats to speculate that he might have lost confidence in Biden's ability to overcome his Republican challenger.