Harbhajan was a part of the Indian squad who jointly won the Champions Trophy in 2002, along with Sri Lanka.
The announcement has come 50 days before the first match of the tournament to be played in London.
Bhajji confident of India winning the trophy
After named as the ambassador for the ICC Champions Trophy, Harbhajan said that he believes India will be able to defend their title this year.
Bhajji said, "If you ask me to stick my neck out and predict the winner, I will happily say India. Yes, I believe this team can defend the title it won in 2013."
Other ambassadors of the tournament
Shahid Afridi of Pakistan, Habibul Bashar of Bangaldesh, Ian Bell of England, Shane Bond of New Zealand, Mike Hussey of Australia, Kumar Sangakkara of Sri Lanka and Graeme Smith of South Africa were named as the ambassadors along with Harbhajan Singh.
The ambassadors will be a part of the Champions Trophy trophy tour and also a part of ICC's editorial team.
Cricketing career of the ambassadors
The eight ambassadors have together played 1,774 ODI matches, scored 51,906 along with hitting 48 centuries and have picked up 838 wickets.