Watch Scarlett Johansson and Craig Campbell Sing 'These Boots Are Made for Walkin' on USO Tour in Afghanistan

Scarlett Johansson and Craig Campbell just performed their first duet live from Afghanistan.

The actress and country star have been hanging out with the troops overseas while on tour with the USO, and this week they decided to team up for a rendition of Nancy Sinatra’s classic “These Boots Are Made for Walkin.’ ”

Campbell set up the performance as part of a new series on his social media channels called Woman Cover Wednesday, in which he covers a song by a different female singer every week.

This week, the “Family Man” singer enlisted a little help on vocals, and had Johansson sing the opening lyrics while he played along on guitar. The stars sang their duet on a couple of folding chairs inside the military base, and had a modest audience of troops listening in from the background.

“It was so great to meet Craig and his band and such a pleasure to see them play each night,” she tells PEOPLE of touring with Campbell. “Chris and I also were totally infatuated with Ray Allen! He is such an incredibly inspirational speaker, I told him he should run for public office!”

This is both Johansson’s and Campbell’s second USO tour. The actress was also joined in Afghanistan by her fellow Avenger, Captain America star Chris Evans. “Getting to hang out with Captain America and Scarlett Johansson was once in a lifetime. They have huge hearts. I feel like I made some new friends with those guys,” Campbell tells PEOPLE of his fellow entertainers.

“The idea that some of our military isn’t going to be with their families over Christmas, it saddens me,” the singer said of volunteering with the USO. “So for me to be able to go to where they are and bring a little home to them is very important to me. I love doing it and am honored to do it.”

Tonight, the USO will announce that they have reached their 75th USO Anniversary goal of America sending one million messages of thanks and support to the troops. To wrap up their 75th anniversary, the USO is asking America to be “the force behind the forces,” and help push that number to 1.4 million messages, which is the number of American troops serving worldwide.

Johansson says she felt lucky to be able to thank the troops for their service in person.

“I think thanking our troops face to face, learning about where they come from, what their families are like and what they do goes such a long way when being so far from home,” she says. “Some of the places we traveled with the USO are some of the most remote. It means a great deal to the visit with the military members there that the USO makes an effort to reach them is such isolated places.”

“I learned just how humble the men and women of the armed forces are. These are true American heroes that are totally down to earth, gracious and open,” she added.