Solano finalised his own move for an undisclosed fee, so he can be nearer his children, who live in London.
Solano Gets His Wish
The Peruvian was allowed to go when it emerged that Habib Beye's £2m switch from Marseille to St James' Park was completed.
Kieron Dyer broke his leg in two places in the midweek Carling Cup win at Bristol Rovers, and West Ham boss Alan Curbishley made a second move for Solano knowing he would not break the bank to get him.
The switch last night brought to an end a two-year stay that started when Graeme Souness brought him back to the club by paying £1.5m to Aston Villa.
He made 52 Premier League starts since that August deadline day in 2005 and he ended up with 210 Premiership starts for the club.
His last appearance for Newcastle was in the 2-0 win over Barnsley on Wednesday night in the Carling Cup.