The fifth edition of the global showdown runs March 8-21 with 20 teams competing in contests in Japan, Taiwan and the United States.
"Once the opportunity came up I was super excited. Looking forward to it," Trout said. "Playing for your country means everything. It's going to be special."
The American lineup also featured Los Angeles Dodgers outfielder Mookie Betts (30), St Louis third baseman Nolan Arenado (31) and Cardinals first baseman Paul Goldschmidt (35) - last year's National League MVP.
Angels teammate Ohtani, a two-way threat as a pitcher and outfielder who was the 2021 AL MVP, will star for two-time Classic champion Japan, which also boasts veteran Yu Darvish (36), a right-handed pitcher for the San Diego Padres who agreed to a $108million six-year contract extension Thursday.
Darvish helped Japan defend the Classic crown in 2009.
Cuba, an amateur dynasty that has been drained of talent by defections over the years, will have Cuban-born MLB talent on the roster for the first time.
Representing the Communist island nation will be Chicago White Sox third baseman Yoan Moncada (27), who in 2014 left Cuba with government permission to pursue an MLB career, and White Sox outfielder Luis Robert (25), who departed Cuba in 2016.
Cuba's baseball federation also picked Cuban-born players on Japanese clubs and US minor-league teams. In past years, Cuban officials did not field players who had left the island in the Classic.
Oddsmakers' darlings to win the crown are 2013 champions Dominican Republic, with the Americans and Japan just behind.
The Dominicans have a superstar lineup including San Diego outfielder Juan Soto (24) and third baseman Manny Machado (30), Toronto first baseman Vladimir Guerrero Jr (23), Boston third baseman Rafael Devers (26) and Seattle outfielder Julio Rodriguez (22).
The Dominicans also feature last year's NL top pitcher - Cy Young Award winner Sandy Alcantara (27) of Miami.
"I always wanted to play in the WBC, play for my country, and to be there this year, I want to do my best," the right-hander said.
New York Mets' shortstop Francisco Lindor (29) was among the stars on the Puerto Rico roster while Venezuela boasted Atlanta outfielder Ronald Acuna Jr (25), Houston second baseman Jose Altuve (32) and reigning AL batting champion Luis Arraez (25) of Miami.