Netherlands international Quincy Promes has left Sevilla for Ajax in a A$25 million deal, the Eredivisie champions have announced.
The 27-year-old, who spent just a single season in LaLiga, has signed a five-year contract in Amsterdam. The fee could rise to €17.2 million (A$28 million) with bonuses.
Ajax are going through a busy off-season, securing a number of key men with new deals while selling Frenkie de Jong to Barcelona and appearing set to see Matthijs de Ligt depart.
Erik ten Hag's men reached the Champions League semi-finals last season, losing to Tottenham in devastating fashion, while winning the league and the KNVB Beker.
Promes, who featured for finalists Netherlands in the Nations League, scoring in a last-four defeat of England, will join the Ajax squad for pre-season on July 8.
He started just 15 times in LaLiga for Sevilla, having earned the move with his strong form for Spartak Moscow.
Promes previously played for Twente and had a loan spell with Go Ahead Eagles.