Atletico Madrid striker Antoine Griezmann has announced he will be leaving at the end of this season after five years.
The World Cup winner signed a five-year contract last June but Saturday's La Liga match against Levante will be his last for the club.
Barcelona will pay the buyout clause in Griezmann's contract of 120m euros, BBC Sport understands.
"It's been an incredible five years. Thank you for everything," he said.
"I wanted to tell the fans who have always given me a lot of love that I have taken the decision to leave, to see other things, to have other challenges," the 28-year-old added, in a video posted on Twitter.
"The truth is it has been difficult to take this route but it is what I feel I need and I would like to thank all of you for the love you have shown me during these five years."
The Frenchman has scored 133 goals in 256 appearances for Atletico since joining from fellow Spanish outfit Real Sociedad in 2014.
He has won the Europa League, the Spanish Super Cup and the Uefa Supercup during his time at Atletico and has been the team's top scorer in each of the last five seasons.
Griezmann rejected an offer from Barcelona last year and revealed his thought process in a documentary called 'The Decision'.
Atletico also reported Barcelona to Fifa over an alleged illegal approach in December 2017.
Griezmann will be the third high-profile player to leave Atletico this summer after defender Lucas Hernandez agreed to join Bayern Munich and long-serving captain Diego Godin announced he would leave, with his contract set to expire.
Coutinho to leave Barcelona? Analysis
David Ornstein, BBC Sport
Antoine Griezmann's impending move to Barcelona will place huge doubt over the future of Philippe Coutinho at the Nou Camp.
Coutinho has struggled to hit top form since joining from Liverpool for £142m in January 2018, and sources I've spoken to say the arrival of Griezmann from Atletico Madrid is likely to see the Brazilian depart.
There will inevitably be speculation around Luis Suarez, too, but he has contributed more than Coutinho and it looks like the Uruguayan will stay this summer before quite possibly leaving in a year's time.
If Coutinho is moved on, I'm hearing a potential destination is Chelsea. The 26-year-old would be among the contenders to replace Eden Hazard - should the Belgium move to Real Madrid.
However Chelsea's hopes of making any signings depend on the outcome of an appeal against their transfer ban to the Court of Arbitration for Sport.