Britney Spears is reportedly planning to sue photographer Dani Brubaker, after private family portraits taken by the snapper were sold to a U.S. magazine.

Brubaker was invited into Brit’s home to take pictures of the wayward singer posing with her boys, Sean Preston and Jayden James, for Brit’s own personal use.

Despite failing to get Brubaker to sign a confidentiality agreement, the photog issued a press release insisting that her "integrity wasn't for sale" after she was allegedly offered big-bucks for the pics by various publications.

However, Brubaker appears to have had a dramatic change of heart on the matter, and recently sold the photos to OK! magazine for a reported fee of "one million dollars."

And Brit is steaming mad!

PageSix reports that Brit will likely hire top legal litigator Howard Weitzman to sue Brubaker for selling the pics.

Their source says that "all legal options are being explored at this time. Brubaker must be dealt with, and Britney will absolutely proceed in the very least to sue her."

Wonder if she'll show up to court for this one?