Chelsea have announced the signing of the winger Mohamed Salah from the Swiss club Basel.
The capture of the Egypt international, which is subject to him agreeing personal terms and passing a medical, could mean Juan Mata's move to Manchester United will now go ahead.
A statement on chelseafc.com read: "Chelsea Football Club can confirm an agreement has been reached with FC Basel for the transfer of their 21-year-old attacking midfielder Mohamed Salah.
"The move is subject to the Egyptian international agreeing personal terms and completing a medical examination."
Provided the finer details of the move are confirmed swiftly, Salah could make his debut in Sunday's FA Cup fourth-round tie at home to Stoke.
He becomes Chelsea's third signing of the January transfer window, following Bertrand Traoré and Nemanja Matic.
José Mourinho made his move after being impressed by Salah's performances against Chelsea as they twice lost to Basel in the Champions League group stages.
Salah scored in three of the Swiss side's four recent meetings with Chelsea – a goal in each of this season's Group E Champions League wins and also netting in the second leg of last term's Europa League semi-final.
Salah was also being courted by Liverpool, who earlier on Thursday conceded defeat in their pursuit of the midfielder.
The move is reminiscent of the deal for Willian, who had already completed a medical at Tottenham before signing for Chelsea last August.
Prior to Kevin De Bruyne's departure to Wolfsburg earlier this month, Mourinho insisted there was no need for a like-for-like replacement for the Belgian, yet now Salah has come in with Mata Old Trafford-bound.
Salah is another option in the attacking midfield roles, but the pace and width he offers suggests Mourinho sees him as an alternative to Mata, rather than a direct replacement.
Mata, Chelsea's player of the year in his two seasons since joining from Valencia, has struggled to cope with Mourinho's demands for a greater work ethic, with Eden Hazard, Oscar and Willian favoured in the three attacking positions behind a lone centre-forward.
Mata has completed just one of the last five games he started and last featured on New Year's Day at Southampton, where he reacted angrily to his substitution early in the second half.