Spears wrote in her post that shortly after a trip to Maui with her fiancé, Sam Asghari, she started to gain weight. She wrote, "So I got a pregnancy test ... and uhhhhh well ... I am having a baby."
The news of the pop star's pregnancy comes months after a judge ended her 13-year conservatorship after a highly publicized legal battle with Spears' father.
She finished her post on a positive note saying, "This time I will be doing yoga every day !!! Spreading lots of joy and love !!!"