The winger moves to Juve on-loan from Nice to the end of the season with an option to buy.
It marks a return to Italy for the former Sassuolo and Atalanta winger.
Boga, presented to the local media this morning, said: "I'm very happy because as a child I dreamed of playing for such a big club, so I'm very happy and I can't wait to get started.
"I'm in the prime of my career, I've seen a lot in my career, and I think it's the right time to play for such a great club . I came here to help the team, which already has very strong players, to play and showcase my qualities: one is dribbling, the other is scoring goals and providing assists.
"I don't think these qualities will go away; they've been inside me since I was a child."
Boga also said: "So I came here to prove I have these characteristics and also to improve in the final meters, so as to score more goals and more assists.
"I'm at the height of my maturity. For me, the Italian championship is always a good league, with very strong teams, and the quality has increased. I'm very happy to return and be back in Serie A.
"Hello to all Juventus fans, I'm very happy to be here. I can't wait to see you at the stadium."