The 31-year-old has struggled for playing time at the Gunners this season and has left for their London rivals on the final day of the transfer window
Chelsea have completed the signing of Olivier Giroud from Arsenal for an estimated £18 million.
The France international will join the Blues on an 18-month contract with an option to extend it for another year after the two clubs agreed a deal on Wednesday.
The move has now been made official after
Arsenal confirmed the signing of Pierre-Emerick Aubameyang from Borussia Dortmund, who have just loaned Michy Batshuayi from Chelsea .
