The 21-year-old only made one senior appearance for Werder, in their Uefa Cup game against Celta Vigo in 2007.

However, he was a regular in their youth sides and has been identified by Arsene Wenger as a bright prospect for the future.

Wenger will hope he has unearthed another gem and is not likely to hesitate in giving Bischoff the opportunity to impress.

The youngster, who can play in the centre of midfield or on the left, will also give Wenger more options following the departures of Mathieu Flamini, Gilberto and Alexander Hleb.

Bischoff will wear the No.28 shirt at Arsenal and link up with his new team-mates when they return from a training camp in Austria.

Bischoff was born in France but has represented Portugal at Under 21 level.