Arsenal have completed the signing of forward Kai Havertz from Chelsea in a deal that ESPN reported last week is worth up to £67.5 million ($85.4m).

The Germany international has signed a long term deal with the north London club and becomes Arsenal's first signing of the transfer window.

"Kai is a player of top quality. He has great versatility and is an intelligent player. He will bring a huge amount of extra strength to our midfield and variety to our play," Arsenal manager Mikel Arteta said.

"We welcome Kai and his family to Arsenal Football Club and we are all excited to start working with him when we start pre-season training soon."