She joins One Call, Girlicious Kristinia DeBarge, the other supporting acts, who were previously announced.
According to Rap-Up.com, a spokesperson for Ciara said she's no longer on the tour, though she opened a few dates in the U.K. No reason was specified.
Meanwhile, some of the only officially released footage from Britney's Circus tour has hit Yahoo!, and features the bat-shit crazy lengthy opening sequence to the performance. And some botchy lip-syncing on the pop princess' part.
Dates and video below.
August 20 Hamilton, ON Copps Coliseum + @ ^
August 21 Ottawa, ON Scotiabank Place + @ ^
August 24 New York, NY Madison Square Garden * + ^
August 25 New York, NY Madison Square Garden * + ^
August 26 New York, NY Madison Square Garden * + ^
August 29 Boston, MA TD Garden * + ^
August 30 Philadelphia, PA Wachovia Center + ^
September 1 Orlando, FL Amway Arena * +
September 2 Miami, FL American Airlines Arena * +
September 4 Atlanta, GA Philips Arena * +
September 5 Greensboro, NC Greensboro Coliseum * +
September 8 Detroit, MI The Palace of Auburn Hills * +
September 9 Chicago, IL Allstate Arena * +
September 11 Des Moines, IA Wells Fargo Arena * +
September 12 Grand Forks, ND Alerus Center * +
September 15 Tulsa, OK BOK Center * +
September 16 Houston, TX Toyota Center * +
September 18 Dallas, TX American Airlines Center * +
September 19 Bossier City, LA CenturyTel Center +
September 21 El Paso, TX Don Haskins Center * +
September 23 Los Angeles, CA STAPLES Center * +
September 24 San Diego, CA San Diego Sports Arena * +
September 26 Las Vegas, NV Mandalay Bay Events Center * +
September 27 Las Vegas, NV Mandalay Bay Events Center * +
*with special guest Jordin Sparks
+ with special guest Kristinia DeBarge
@ with special guest Girlicious
^ with special guest One Call