Both the GP2 and GP3 season lost a round to the cancellation of Formula 1's German Grand Prix, but organisers had always intended to replace this event.
After talks with a number of potential venues, including Qatar's Losail track, a deal has been struck with Bahrain and the WEC to stage the round on November 19-21.
"I am pleased to confirm that we have added Sakhir to our 2015 GP2 calendar in November," said GP2 CEO Bruno Michel.
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"Ever since the announcement of the cancellation of the German event, we have been working hard to try and add a round for our series.
"It was important that we could keep the costs down for the teams, but also to find a venue that was an added value for the drivers.
"Bahrain was the best option: not only is it a Formula 1 track, but it makes perfect sense to have it back-to-back with the final round of the season in Abu Dhabi."
The event takes place one weekend before the season finale for both championships in Abu Dhabi.
While GP2 held its opening round on the Bahrain GP F1 bill in April, the event will be GP3's first visit to Sakhir.
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