Egyptian forward Mohamed Zidan started his new career at Dortmund as he began training with his new teammates on Tuesday morning.
A statement on the club's website announced that the 26-year old striker will wear the number 10 jersey that belonged to Mladen Petric who moved to Hamburg in a swap deal.
The report underlined that Zidan has always delivered his goods under the helms of coach Jurgen Klopp who has been hired by Dortmund this season.
The 2008 African Nations Cup winner scored 22 goals in 41 appearances with Klopp at Mainz.
Dortmund had a successful start of their 2008/2009 campaign as they beat Bayer Leverkusen 3-2 last week-end.
They will have a tough task against defending champions Bayern Munich next Saturday.