The popstar will play 20 shows across Canada and the US during the additional dates, which start off in Ontario on August 20 before concluding on September 27 in Las Vegas, Billboard reports.
"I'm so excited to bring The Circus back to North America. I've made some really cool changes to the show that I think my fans are really going to love. I also get to bring the show to some new cities we missed the first time around," she said in statement.
Spears's current jaunt is reportedly the highest grossing tour of 2009 so far.
Yesterday, the singer announced that she will play in Australia for the first time, while last week, she kicked off a European leg at London's O2 arena.