President Obama officially endorsed Hillary Clinton for president in a video posted to YouTube today, shortly after she reached the number of delegates to become the presumptive Democratic nominee—the first woman to do so in either major political party.

“Look, I know how hard this job can be,” Obama said, praising Clinton's experience as a senator and Secretary of State. "That’s why I know Hillary will be so good at it... In fact I don't think there ever been someone so qualified to hold this office."

The president also addressed the friction between her backers and Bernie Sanders' boosters, reminding viewers that his race against Clinton eight years ago was pretty intense, too.

To date, Sanders has yet to concede to Clinton, but said he looks forward to working with her to defeat Donald Trump in the general election.

President Obama is expected to join Clinton at a campaign rally in Green Bay, Wisconsin, next Wednesday.