The 31-year-old left-hander will replace Essex's foreign player Hamish Rutherford of New Zealand for the remainder of the season. "I am delighted to have this chance to make my county cricket debut with Essex," Gambhir was quoted as saying by Essex on their Twitter page.
Gambhir is expected to make his Essex debut in the LV= County Championship match with Northamptonshire for the Colchester Cricket Festival at Castle Park on August 20 and will be available for the remaining LV= County Championship and Yorkshire Bank 40 matches of the season, a report on the team's website said.
Commenting on the signing Essex Head Coach Paul Grayson said: "We are delighted with the signing of Gautam Gambhir who is a player with pedigree, which has been showcased on the biggest stages in cricket. He will no doubt bring his experience to the squad during an important stage of the season for us in the LV= County Championship and Yorkshire Bank 40 competition."