Katy Perry feels "insulted" by estranged husband Russell Brand, it has been revealed.

Russell Brand filed for divorce from Katy in late December after 14 months of marriage.

Katy is reportedly incensed by Russell's attitude.

"Katy is insulted and feels betrayed that Russell has treated her so poorly," an insider told Us Weekly. "She will never forgive him. Ever."

When Russell moved his belongings out of Katy's Los Angeles mansion last weekend, the pair were rumoured to have discussed how to proceed with their divorce. Katy may have not liked what she heard, as she wants little to do with Russell in the future.

"[Katy is] limiting [her] interactions [with Russell]," another source told the magazine. "He's being so atrocious that she feels like she never knew him."

Russell announced that he will be penning a memoir in the near future. Katy is reportedly nervous about the tome, which will cover the couple's marriage in detail.

"[Russell] wants to tell his side of the story," a source told Us Weekly earlier this month. "The book will cover his married life, the breakup and moving on. And I don't think he plans on keeping the breakdown of the marriage a secret. Pardon the pun, but Russell is an open book."

The pair, who wed in a lavish Hindu ceremony in India in October 2010, are currently working on finalising asset allocation and other divorce details.