A high school student scored an exclusive interview with Pentagon chief Jim Mattis after an aide of President Donald Trump inadvertently exposed the defense secretary's cell phone number.

The Washington Post in May ran a photo of Trump and his bodyguard Keith Schiller walking outside the White House, with Schiller clutching a bunch of papers.

Sharp-eyed readers noticed that atop the papers was a yellow sticky note that said 'Jim, Mad Dog, Mattis' along with a phone number.

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Teddy Fischer, a sophomore from Mercer Island High School, saw the number and called Mattis with an interview request

Mattis surprised the high school student by taking time for a 45-minute interview for his school newspaper. Mattis is seen above awaiting the arrival of Tunisian Prime Minister Youssef Chahed during an honor cordon ceremony at the Pentagon July 10

Retired four-star Marine general Mattis has been nicknamed 'Mad Dog' by some in the media and by troops that served under him.

The newspaper quickly took the photo down but not before Teddy Fischer, a sophomore from Mercer Island High School saw the number and called Mattis with an interview request.

'I called it to see if it was him, because I was pretty curious if this is actually his number or is it kind of a joke,' Fischer told the King 5 local news channel in his home state of Washington.

He didn't leave a message but went on to text an interview request.

To his surprise, Mattis called back and agreed to schedule an interview, which ultimately would last for about 45 minutes.

What followed was a far-ranging conversation across political topics and history.

'I called it to see if it was him, because I was pretty curious if this is actually his number or is it kind of a joke,' Fischer told the King 5 local news channel in his home state of Washington. He didn't leave a message but went on to text an interview request, seen above

'Especially if you study history, you realize that our country has been through worse,' Mattis said when asked what advice he would give a current high schooler scared about what they see on the news.

When asked why he had chosen to call Fischer back, Mattis said it was partly because he too comes from Washington state.

'I've always tried to help students because I think we owe it to you young folks to pass on what we learned going down the road so that you can make your own mistakes, not the same ones we made,' Mattis said.

The full transcript of the interview can be viewed at the high school's The Islander newspaper.