A statement by Barcelona confirming the deal read;
"FC Barcelona and Atletico Madrid have reached an agreement for the loan of Antoine Griezmann for a season with the option of a further season," the statement said.
"The Madrid club will pay the player's wages and there is a compulsory permanent transfer clause.
"FC Barcelona would like to thank Antoine Griezmann for his commitment and dedication and wishes him all the best for the future."
The French forward spent five seasons with Atletico Mafrid before joining Barcelona and was the Rojiblancos, fifth top scorer of all time.
Since joining Barcelona in 2019, Griezmann registered just 35 goals.
Griezmann becomes Barcelona's third transfer deadline day sale after right-back Emerson Royal moved to Premier League side Tottenham Hotspur for a reported £25.8 million and teenage midfielder Ilaix Moriba also joining RB Leipzig for £13.7 million.
Atleti on the other side managed to secure the services of the former Real Soceidad forward after releasing midfield dynamo Saul Niguez to join Chelsea in another deadline day deal.
The left-footed striker scored 133 goals in 257 games during his spell at the Wanda Metropolitano Stadium, winning the Europa League, Uefa Super Cup and Spanish Super Cup during his time in the Spanish capital.
With Atletico Madrid looking to defend the LaLiga tile, Griezmann is exepcted to feature once again for his former club when he returns from the international break.
The arrival of Griezmann will bolster Diego Simeone's attacking departement which already have the likes of experienced Luis Suarez and Argentine striker Angel Correa.
