Ever since Barcelona signed a (somewhat controversial) sponsorship deal with Qatar Airways a few years ago, there was an understanding before the two parties that the Catalan club would play a friendly in Qatar at some point throughout the duration of the contract.
The first four years of the deal came and went and no friendly was scheduled, although it came close to happening a few months ago. Another contract has been signed between Qatar and Barça, and since the friendly was apparently an obligatory condition to get the deal done, the game will finally happen.
Mundo Deportivo reports that the Catalan giants agreed to play a friendly against Al Ahli from Saudi Arabia, who have already announced the match in their official website.