Chelsea have announced the signing of French forward Olivier Giroud from Arsenal on an 18-month contract.

Giroud, 31, will wear the number 18 shirt for his new club, and it is understood that the transfer figure is £17.5m.

Speculation linking the Frenchman with a move to Stamford Bridge gathered pace when Arsenal announced the signing of Pierre-Emerick Aubameyang from Borussia Dortmund.

The Premier League champions have now confirmed the capture of a player that scored 105 goals in 253 appearances for Arsenal.

Giroud told the club's official website: "Chelsea is one of the biggest teams in the Premier League. They have won maybe the most trophies in the last six or seven years. It's a massive club and I am proud to sign for Chelsea, and I'm looking forward to playing."

Meanwhile, Chelsea director Marina Granovskaia added: 'Olivier is a proven talent at the top level and we are very pleased to call him a Chelsea player.

"He has scored goals regularly throughout his career and is well accustomed to English football and the Premier League. We are sure he will be a fantastic signing."

The signing of Giroud has allowed Michy Batshuayi to leave Stamford Bridge to join Borussia Dortmund on loan.