LaLiga champion Barca will take on the Partonepei in a two-legged clash in the United States.
The first game will be played at Miami's Hard Rock Stadium on 7 August, with the second clash held at the Michigan Stadium three days later.
"Visiting the United States and being able to get closer to our fans is always a great thing for Barca," Barcelona president Josep Maria Bartomeu said. "On top of that, we will also have the chance to play at two iconic stadiums: at Hard Rock Stadium in Miami, where in 2017 we played the LaLiga Clasico, and at Michigan Stadium, the largest in the United States.
"While there, we hope to put on a show and entertain our American fans with our style of play."
Barca previously confirmed it will play Chelsea and Vissel Kobe – whom former Blaugrana players Andres Iniesta, David Villa and Sergi Samper now represent – during a Japan tour in late July.
The inaugural competition will see Napoli make a long-awaited return to the States.
"We could not be happier to be playing against Barcelona in the United States," Napoli president Aurelio de Laurentiis said. "Our club has not visited the country for thirty years and the chance to go back to the American market for these two games and against an opponent like Barca is extraordinary for us."