Charley Keyes
CNN Senior Producer

Secretary of State Hillary Clinton congratulated the oldest Peace Corp volunteer in the world on Tuesday, an 85-year old Florida woman serving in Morocco.

Clinton praised Muriel Johnston “as one of the best” in a meet-and-greet session of U.S. Embassy officials and other Americans in Marrakech, Morocco. Clinton was representing the U.S. at international conference in Morocco, on a trip that stretched from Pakistan to the Middle East.

Johnston is volunteering as a health worker in the Moroccan province of Azilal. She hails from New York but has lived in Sebastian, Florida since 1912. And Peace Corps headquarters in Washington confirms that she is the oldest Peace Corps volunteer – currently serving.

“I have to recognize – I just learned about this last night – Muriel Johnston. Muriel? Stand up, Muriel,” Clinton said to applause and cheers of Johnston’s fellow Peace Corps workers and other Americans.

“My young staff said, “Oh my goodness, Muriel Johnston, she’s the oldest Peace Corps volunteer in the world.” I said, “That’s not the way we think about it. No, Muriel and I might say she is one of the best Peace Corps volunteers in the world,” Clinton said to more applause.

“And it’s also a great reminder that in America in the 21st century, there are not only second acts; there’s third acts and fourth acts and fifth acts and – if you’re ready to embrace new challenges,” Clinton said.

She is one of more than 7,600 Peace Corps volunteers serving in 75 countries.

Later Clinton shook hands with Johnston and asked if she was enjoying herself. “I’m having a wonderful time," Johnston told the Secretary.