Vice President Joe Biden Officiated His First Wedding for Same-Sex Couple

Two longtime White House staffers tied the knot.

Biden officiated over the wedding of two longtime White House staffers, Brian Mosteller and Joe Mahshie, at the Naval Observatory on Monday, his office said.

Posting a photo of the ceremony on Twitter, Biden wrote, "Proud to marry Brian and Joe at my house. Couldn't be happier, two longtime White House staffers, two great guys."

Biden's wife, Jill, later tweeted: "Love is love!"

ABC News' Arlette Saenz contributed to this report.