As well as winning a long court case on Thursday, she has now revealed that she is expecting a baby.
The baby will be JK's second child. She already has a nine-year-old daughter called Jessica from her first marriage.
The magical author started writing the Harry Potter books while she was a single mum in a café in Edinburgh.
She wrote them intended for her daughter because JK felt there wasn't anything new to read to her.
The baby is due next spring - but will it be Harry or Hermione?