Spears was regularly spotted out partying with Hilton following her split from husband Kevin Federline, but her antics led to a huge amount of bad press and a backlash from fans.
Her spokesperson explained: "Britney had fun with Paris. But she wants to focus on her family and career now."
Hilton had invited Britney to accompany her to the Vienna Opera Ball, hosted by Richard and Christina Lugner, but she has now withdrawn the offer.
Richard said: "Paris is a very good advertisement for the Opera Ball. But she will no longer be joined by Britney."
Christina added: "They unfortunately do not get on any more. But Paris is very happy."