Griezmann wants to join Messi at Barcelona from Atletico Madrid when the transfer window reopens, having revealed earlier this week he would be leaving the La Liga giants after five successful years.
The France international, who turned down a transfer to the Nou Camp back in the summer, said on Tuesday: "After talking with Cholo [Diego Simeone], Miguel Angel and the people from the offices, I wanted to talk to the fans who have given me a lot of love.
"I have decided to leave, see other things, have other challenges and with great difficulty, this is what I feel and I need.
"It's been five great years where I've won my first important trophies with a club. It's been a very important stage.
"I have enjoyed a lot, I have left everything in the field, I have tried to behave well, I have tried to give joy to the people who have come to the Metropolitano and also away from home, and I only have gratitude for all of you.”
It was reported on Friday that Griezmann had told Atletico he wants to play alongside Messi next season after a phone call with the Argentina international.
However, Catalan newspaper Sport insist this is not the case.
They say that, behind closed doors, Messi has assured Barcelona players he has not called the France international about a transfer.
Certain members of the dressing room are also opposing a deal for the World Cup winner.