Marking their 28th wedding anniversary, former US President Barack Obama and his wife Michelle urged people to cast their ballots during the November 3 presidential election.

The couple shared photos on Instagram on Saturday to mark the day. Alongside his photo, the former President said: "Even with everything going on, I wanted to take a moment to say happy anniversary to the love of my life. Every day with Michelle Obama makes me a better husband, a better father, and a better human.

Michelle and Barack Obama
Barack Obama and Michelle Obama pose for a formal portrait on December 6, 2009Lawrence Jackson/White House via Getty Images

"This year, while we appreciate all your well-wishes, what we'd really love is for each of you to reach out to one person in your life who might not vote. Help them get registered. Help them make a plan to cast their ballot. Send them to iwillvote.com to get started."

In her post Michelle Obama said: "Twenty-eight years with this one. I love Barack Obama for his smile, his character, and his compassion. So grateful to have him as a partner through everything life throws at us.

"And this year we have a request for you... Pick one person in your life who might not vote and make sure they do. Tell us about it in the comments! That's an anniversary message of the best kind."

While the former President's post has garnered 2.2 million likes, Michelle Obama received more than 3 million likes.