The transfer from one London power to another is in the £18 million range, according to reports.
Chelsea have completed the deadline day signing of Arsenal striker Olivier Giroud, a deal that will see the France international move across London in a transfer believed to be worth £18m.
Giroud replaces Michy Batshuayi at Stamford Bridge as a result of the Belgian's loan to Borussia Dortmund to fill the void left by Pierre-Emerick Aubameyang's move to Arsenal earlier in the day.
Brought in as support and competition for Alvaro Morata, he has signed an 18-month contract with Chelsea that will keep him at the club until the end of the 2018/19 season.
Although the No. 12 shirt he wore at Arsenal and for France was available, Giroud has been assigned the No. 18 shirt for the Blues.
"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," Giroud old Chelseafc.com.
Giroud leaves Arsenal after scoring 105 goals in just over 253 appearances since first joining the club in 2012. His best single season Premier League return to date came in the 2013/14 and 2015/16 campaigns when he found the net on 16 occasions.
In the latter season, he managed a total of 24 goals in all competitions.
Now 31 years of age, Giroud first rose to prominence during his time with Montpellier as the club from the south of France shocked Ligue 1 to claim an unlikely title in 2011/12.
It was only Giroud's second ever season of top-flight football after starting out in the lower leagues, but he finished the campaign as the league's joint top scorer with 21 goals.