The agreement includes an initial payment of €63.5 million (£54.8m) plus €10m in add-ons for the Portuguese international. Gyokeres scored 54 goals in 52 games for Sporting last season.
Gyokeres may complete his move in time to join Arsenal's preseason tour in Asia. This is great news for fans who have been calling for a striker this summer. He will reportedly wear the No 14 shirt, previously worn by Thierry Henry, a huge honour for Gyokeres.
Arsenal will play Newcastle United and Tottenham Hotspur in Asia, where Gyokeres is expected to make his debut in an Arsenal shirt alongside Noni Madueke. The arrival of Gyokeres will be a major relief for the club, which has been without a recognised No 9 for much of the season.
Arsenal's new striker will help the team challenge against top teams like Liverpool, Chelsea, and Manchester City, who have made attacking improvements. The club will aim for the title with Gyokeres on board, providing firepower up front.