The Belgium international has agreed to a season-long deal with the Toffees and will be joined by two other last-minute signings.
The club confirmed the signing of three players, James McCarthy, Romelu Lukaku and Gareth Barry, who all joined the club in the final minutes of the summer window on Monday.
Former Wigan star McCarthy joined on a long-term deal from 13 million pounds, while Chelsea striker Lukaku and Manchester City midfielder Barry have both joined the club on season-long loan deals. For Lukaku, it marks the second consecutive season that he leaves on loan from Chelsea to a Premier League club. He tallied 17 goals with West Brom last season.
The inbound transfers helps lessen the blow of losing two players, as Everton saw Marouane Fellaini make a big-money move to Manchester United and Victor Anichebe bolted to West Brom. The two outbound transfers net the club upwards of 30 million pounds.