Lucas Paqueta signs for Flamengo in record South American deal
The Brazilian Paqueta, 28, was cleared in July of spot-fixing allegations that have hung over him and were seen as costing him a likely move to Manchester City two years ago.
West Ham said they had tried their best to convince him to stay, but "reluctantly" agreed to the transfer.
"Lucas has made it clear that, for personal and family reasons, he wishes to return home to Brazil and make a fresh start," said the statement.
The club confirmed that Paqueta "has been given permission to undergo a medical and discuss personal terms with Brazilian club Flamengo, after a fee was agreed for his permanent transfer."
The record sale brings Paqueta back to Flamengo where he began his career before taking the leap to Europe in 2019.
Previously with AC Milan and Lyon, Paqueta played 18 matches for West Ham in the Premier League this season, scoring four goals.
Flamengo president Luiz Eduardo Baptista told journalists on Sunday he was focused on closing "the biggest transaction ever made by a football club" in South America.
Flamengo are one of Brazil's most successful and richest clubs, and last year won the Copa Libertadores and the Brazilian title.
Brazilian media reported Paqueta had been signed for 42 million euros, before tax.
Last year, Flamengo paid 31.6 million euros for winger Samuel Lino from Atletico Madrid, according to their financial statements.
Brazilian clubs have a combined revenue approaching $2 billion, according to the latest annual report from the investment firm Galapagos Capital, thanks to a massive domestic market of more than 200 million people.
This financial power gives Brazil a significant advantage in the region.
Paqueta -- who was part of the 2022 World Cup team -- hopes to represent Brazil again this year at the tournament held in the United States, Mexico, and Canada between June 11 and July 19.
The midfielder is emerging from a two-year cloud of suspicion as England's Football Association (FA) investigated whether he was deliberately getting yellow cards after a series of suspicious betting patterns were noted.
The player maintained his innocence and after his acquittal, said he could "play football again with a smile on my face."