Marcos Alonso has completed his return to the Premier League with a move to Chelsea from Fiorentina.
Chelsea have signed Marcos Alonso on a five-year deal from Fiorentina.
Former Bolton Wanderers and Sunderland left-back Alonso had been linked with a move to Chelsea late in the transfer window, though the Italian club denied such reports on Monday.
However, Fiorentina announced the sale of the 25-year-old defender to the Premier League team on Wednesday, with Chelsea then later confirming the deal.
"I'm very happy. It's a step up in my career and I think this is the perfect place for me to continue developing. It's time for me to win some titles," Alonso told Chelsea's official website.
"It was an easy decision for me to make when I heard the club were interested in signing me.
"My family and close friends know Chelsea is the club I have dreamed about playing for so I'm really excited about the challenge and I'm looking forward to working with my new team-mates."
The west London club have been looking to bolster their options at left-back following Baba Rahman's loan to Schalke this month.
Alonso will battle with compatriot Cesar Azpilicueta for the left-back berth, though the latter can also play at right-back.
The deadline day deals may not be done for Chelsea, with Paris Saint-Germain defender David Luiz reportedly set to return to Stamford Bridge.