WASHINGTON (CBS/NNS)-- An American University student received more than just a diploma during her graduation ceremony in Washington D.C. Sunday (5/13). She got a lifetime commitment.

As Sarah Cooper walked across the stage to collect her diploma, she didn’t expect to receive a diamond ring as well.

Diploma in hand she prepared to walk off the platform. That’s when her boyfriend, Sam Miller, got down on one knee and popped the question.

A shocked, but excited Cooper said yes, then kissed Miller in front of family, friends, professors and peers.

Cooper, a Marlboro, New Jersey native, was a Justice, Law and Society major in AU’s School of Public Affairs. But after she realized her dream was to teach. She added a secondary teaching degree to her JLS major.

Miller, who also graduated from AU, was a Public Communications and Psychology double major. He grew up in South Bend, Indiana.

The happy couple were dating for four years.