Neymar has signed a five-year contract with Paris Saint-Germain after paying a release clause to leave Barcelona, the French club has announced.
The Brazilian winger, 25, is committed to Paris Saint-Germain until June 2022.
He forced his way out of Camp Nou by paying a world record EUR222 million ($332m) release clause.
"I am extremely happy to join Paris Saint-Germain," Neymar said in a statement.
"Since I arrived in Europe, the club has always been one of the most competitive and most ambitious. And the biggest challenge, what most motivated me to join my new teammates is to help the club to conquer the titles that their fans want."
"From today, I will do everything I can to help my new teammates, to open up new horizons for my club and to bring happiness to its millions of supporters around the world."
PSG were similarly effusive after the arrival of what fans hope will be the missing piece in the hunt for an elusive Champions League crown.
"Today, with the arrival of Neymar Jr, I am convinced that we will come even closer, with the support of our faithful fans, to realising our greatest dreams," club president Nasser Al-Khelaifi said.
Barcelona signed Neymar in 2013 from Santos, with the winger scoring 105 goals in 186 games, as he helped Barcelona win a Champions League, two La Liga titles and three Spanish Cups among other trophies.
He also won Olympic gold on home soil last year with Brazil in a dramatic penalty shootout win over world champions Germany.
