Neymar has joined Saudi club Al Hilal from Paris Saint-Germain, according to Anadolu Agency.
"I am here in Saudi Arabia, I am HILALI," the 31-year-old star said in a video message on Twitter.
The duration and financial details of the deal were not disclosed.
In a farewell message, Nasser Al-Khelaifi, the president and CEO of Paris Saint-Germain, said: "It is always difficult to say goodbye to an amazing player like Neymar, one of the best players in the world."
"I will never forget the day he arrived at Paris Saint-Germain, and what he has contributed to our Club and our project over the last 6 years," he said on PSG's official website.
Neymar helped PSG reach their first-ever UEFA Champions League final in 2020. He also helped Barcelona win the 2015 Champions League and two Spanish La Liga titles in 2015 and 2016.