Borussia Dortmund have signed Germany Under-21 international midfielder Maximilian Philipp from Freiburg for a reported €20million fee.

Dortmund announced the 23-year-old's signing on Wednesday, with Philipp having agreed a five-year contract for Peter Bosz's side.

He played 25 times for seventh-placed Freiburg in last season's Bundesliga, scoring nine goals including one in a 3-1 away defeat to Dortmund in September.

"BVB are one of the biggest clubs in the world. It is an honour for me to be able to play here," Philipp told the club's website.

"I think that at 23 I am mature and old enough to be able to take this step. Now I want to develop further at Dortmund."

It has been a busy week for Dortmund, who appointed Bosz to succeed Thomas Tuchel as head coach on Tuesday, and signed teenage defender Dan-Axel Zagadou from Paris Saint-Germain. 

The club have also signed Omer Toprak and Mahmoud Dahoud from Bayer Leverkusen and Borussia Monchengladbach respectively, with Philipp the club's fourth signing.

Sporting director Michael Zorc added: "We are delighted to have secured in Maximilian Philipp a player who was sought after at home and abroad. He has brilliant prospects."

Philipp will represent Germany at the Under-21 Euros and then take a three-week break before joining up with his new team-mates.