Branislav Ivanovic's long association with Chelsea has ended with the Serbian joining Zenit St Petersburg on a three-and-a-half year deal.
The 32-year-old defender, who made 376 appearances in all competitions for Chelsea since he moved to Stamford Bridge in 2008, had also been linked to Everton before the transfer deadline.
A statement published on Zenit's official website said the two clubs had agreed the switch, for an undisclosed fee, of a player whose contract was due to expire at the end of the season.
Ivanovic won the Premier League title twice, the FA Cup three times, the Champions League - although he missed the 2012 final due to suspension - and the Europa League with the Blues.
He featured in 13 league outings for Chelsea this term, scoring his last goal for Antonio Conte's table-toppers in Saturday's 4-0 FA Cup defeat of Brentford.
Zenit, who are managed by Mircea Lucescu, are 17 games into their Russian Premier League campaign and sit five points behind Spartak Moscow.