The 22-year-old will link up with his new team-mates when they return for pre-season after signing what the club describes as a "long-term" contract.

Fabianski has made four appearances for his country and was voted the Polish league's best goalkeeper for the previous two seasons after some fine performances for former club Legia Warsaw.

Wenger told the club's official website www.arsenal.com: "We are pleased to have signed Lukasz Fabianski.

"He is a very good young goalkeeper who will provide good support to our squad.

"He has performed consistently well for Legia Warsaw in recent seasons and was rightfully rewarded with a place in the Polish World Cup squad.

"Lukasz will be a big asset to our squad and we are looking forward to him joining us for pre-season."

The Gunners boss has previously spoken of his belief that the Pole can compete with first-choice goalkeepers Jens Lehmann and Manuel Almunia as soon as he arrives at the Emirates Stadium.

Fabianski added: "I am delighted to be joining Arsenal.

"They are a great club with many world-class players and I am really looking forward to meeting my new team-mates.

"Arsenal is one of the biggest and best clubs in Europe and I hope that I can help the team win trophies in the future."

Meanwhile Mart Poom has joined relegated Watford from Arsenal in a permanent deal for an undisclosed fee.

The Estonian goalkeeper, who has made 112 international appearances for his country, joined the Gunners from Sunderland, initially on loan in August 2005. The move was made permanent the following January.

The 35-year-old made two first-team appearances during his time with Arsenal, making his Premiership debut for the Gunners in the last game of the season at Portsmouth.