The 31-year-old Danish midfielder has joined for a reported initial £10 million ($14 million) fee plus a further £2 million in add-ons, according to The Athletic.

Norgaard scored 13 times in 196 appearances for the Bees and was crucial to establishing Brentford as a Premier League club over the past four seasons.

"We’re delighted to welcome Christian to Arsenal. He is an international player with a wealth of experience of the Premier League. He has proven leadership skills and a strong character which will be invaluable to our squad," Arteta said in an Arsenal statement.

"He is a strong midfielder with excellent tactical awareness and versatility. He also has physical presence and intelligence which will give us added depth and balance."

Norgaard is Arsenal's third signing of the transfer window after Spanish midfielder Martin Zubimendi and goalkeeper Kepa Arrizabalaga.

Arsenal are also reportedly closing in on the signing of Swedish striker Viktor Gyokeres from Sporting Lisbon for a deal worth around £70 millon.