The US-born 21-year-old, grandson of double world champion Emerson Fittipaldi, broke the news during a television interview at the Sao Paulo Grand Prix and posted a picture on Twitter of himself with Red Bull motorsport head Helmut Marko.
Fittipaldi is in his first full season in Formula Two with Charouz, sixth in the championship with a round to spare but tied on points with India's fifth-placed Jehan Daruvala and fourth-placed Australian Jack Doohan.
He was part of the Ferrari Driver Academy before leaving last year.
"On future plans, let's see, but I'm very happy for being part of the Red Bull drivers' academy," he told Reuters at the Interlagos paddock.
The four Fittipaldis to race in Formula One are 1972 and 1974 champion Emerson, Enzo's brother Pietro, great-uncle Wilson and cousin Christian.
Pietro (26), a reserve driver at Haas, was the last Brazilian on the Formula One grid when he replaced Romain Grosjean for two races in 2020.
Brazil, one of the most successful countries in the sport's history, has not had a regular race driver since Felipe Massa's retirement in 2017.
"Very special news at a critical moment (for Brazil) as we haven't had a driver in F1 for years," Emerson told Reuters at Interlagos.
"These emerging talents are our hope," he added, also praising this season's F2 champion Felipe Drugovich (22) who is now a reserve for Aston Martin.
