Former President Barack Obama and former first lady Michelle Obama have endorsed Kamala Harris in her White House bid, giving the vice president the expected but still crucial backing of the nation’s two most popular Democrats.

The endorsement, announced Friday in a video showing Harris accepting a joint phone call from the former first couple, comes as Harris builds momentum as their party’s likely nominee after President Joe Biden’s decision to end his reelection bid and endorse his second-in-command against Republican nominee and former President Donald Trump.

It also highlights the friendship and potentially historic link between the nation’s first Black president and the first woman, first Black woman and first person of Asian descent to serve as vice president, who is now vying to break those barriers at the presidential rank.