Chelsea sign Arsenal striker Olivier Giroud for £18m.

Chelsea have signed Arsenal striker Olivier Giroud on an 18-month deal for about £18m.

France international Giroud, 31, leaves Arsenal having scored 105 goals in 253 games since joining Arsenal.

Earlier on the closing day of the winter transfer window, Dortmund sold Pierre-Emerick Aubameyang to Arsenal.

Giroud: "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's final appearance for Arsenal was as a substitute in Tuesday's 3-1 defeat by Swansea.

After his move to Chelsea was confirmed, Giroud thanked Gunners fans for their part in a "beautiful story" after "five and a half amazing years within the Arsenal family".

"I would like to especially thank the fans for their unconditional support upon my arrival," he wrote on Twitter.