Birmingham have completed the permanent signing of Poland midfielder Krystian Bielik.
The 25-year-old previously enjoyed two loan spells with Blues but has now signed a three-year deal from Derby for an undisclosed fee.
Bielik told BluesTV: “I am honestly buzzing.
“We have been working with Birmingham for the last couple of weeks. We talked about this, we talked about the project and what we want to achieve.
“I fully believe in this, so that is why I am back. It has been a good last year for me personally and the club as well. We are going to push for more this season.”