Ivanov joins Partizan Belgrade
The 23-year old central defender has made 16 international appearances and will replace former Yugoslavia defender Mladen Krstajic, who was named Partizan's managing director last month after retiring at the end of the season.
"I had offers from several clubs and decided to join Partrizan because of the club's high ambitions in domestic competitions and Europe," Ivanov told reporters.
"I asked [Bulgaria coach and Partizan's former manager] Lothar Matthaus for advice and he told me to join Partizan because they are one of the best clubs in the Balkans.
"My personal ambition is to be a worthy replacement for Krstajic and help the club retain the domestic double, as well as to do have a successful campaign in Europe."
Partizan reached the Champions League group stage for the first time under Matthaus in 2003 and again last season, but finished bottom of their group both times after failing to win a single match.
This month Partizan signed defensive midfielder Sasa Markovic from city rivals OFK and have been linked with South Korea striker Yoo Byung Soo after their top scorer Ivica Iliev joined Polish side Wisla Krakow.