The 'I Wanna Go' singer had previously announced a full arena tour for October and November and has added new shows in London, Newcastle and Sheffield.
Spears has already unveiled the 21-track setlist for the tour, including two 'surprise songs'.
The US leg of the tour has received positive reviews from the American media.
Tickets for the new dates go on sale this Friday, July 1 and are priced at £50 and £55.
The updated tour dates are as follows:
- October 27 - London, O2 Arena
- October 28 - London, O2 Arena - new date
- October 30 - Birmingham, LG Arena
- October 31 - London, Wembley Arena - new date
- November 3 - Newcastle, Metro Radio Arena - new date
- November 5 - Sheffield, Motorpoint Arena - new date
- November 6 - Manchester, MEN Arena
Watch Britney Spears talk to Daybreak about her 'Femme Fatale' tour below: