The 22-year-old joins for a fee of €40million (£34.3m; $46.2m) and has signed a four-year deal, with the option of a further year.

Diomande represented Ivory Coast at the World Cup this summer, alongside Forest midfielder Ibrahim Sangare.

Nottingham Forest is finalizing a €40 million deal for Sporting CP centre-back Ousmane Diomande, with personal terms agreed and negotiations