Everton triggered Onyekuru's release clause with a £7 million bid and reportedly believed completed a medical at the club's Finch Farm base on Monday.
After all, the Nigerian scored 24 goals and provided nine assists for the Belgian club last season and he is exactly what West Ham need to ensure they improve in Slaven Bilic's third year at the helm.
Under the terms of the move claimed by Sportwereld and DH, Onyekuru would be acquired by the Blues and then move to the Constant Vanden Stock Stadium on a season-long loan where he could continue his development.
After being wooed by several top clubs in Europe, Nigerian striker, Henry Onyekuru has finally sealed a deal with EPL club, Everton FC.
No fee was reported.
English goalkeeper Jordan Pickford arrived from Sunderland for £30 million (S$52.9 million) and Dutch worldwide midfielder Davy Klaassen cost £25 million pounds from Ajax.
Ronald Koeman is still after his prime summer target Gylfi Sigurdsson and Burnley defender Michael Keane.