The 40-year-old pop star announced the news in a lengthy Instagram post on Monday morning, writing: ‘So I got a pregnancy test … and uhhhhh well … I am having a baby.’
However, the Baby One More Time hitmaker confused fans as she added in her caption that she was ‘a little food pregnant’ and had taken a pregnancy test after noticing that she had gained weight while on vacation.
It will be the first child for the singer and fiancé Sam Asghari, while Britney has two sons Sean Preston, 16, and Jayden James, 15 from her previous marriage to Kevin Federline.
Sam also confirmed the pregnancy news in a post on Monday, writing: ‘Marriage and kids are a natural part of a strong relationship filled with love and respect.
In her announcement post, Britney also spoke about suffering perinatal depression during her first two pregnancies.
Britney explained: 'It's hard because when I was pregnant I had perinatal depression.'
'I have to say it is absolutely horrible… women didn't talk about it back then … some people considered it dangerous if a woman complained like that with a baby inside her but now women talk about it everyday … thank Jesus we don't have to keep that pain a reserved proper secret.'
The pregnancy news comes after it was claimed that the Toxic singer forced onto birth control while she was under her 13-year-long conservatorship, that was terminated last November.
In a court hearing in June last year, Britney spoke out against her conservatorship publicly, as she said she feels 'traumatized' by the controlling system she has been placed under.
She said: 'I am not happy, I can't sleep. I'm so angry, it's insane. And I'm depressed. I am traumatized. I just want my life back.
'I want to end this conservatorship without being evaluated. This conservatorship is doing me way more harm than good. I deserve to have a life, I've worked my whole life. I deserve to have a two to three-year break.'
The Toxic hitmaker accused her father and her conservatorship team of refusing to allow her to marry her boyfriend, Sam, 28, or have children with him.
Britney claimed her conservators have made her get an IUD as a form of birth control so she cannot currently have children, even though she wanted to 'get married and have a baby' with Sam.
The star slammed her situation as 'abusive', and even called for her father and those involved with her conservatorship to be 'jailed'.
She fumed: 'They have me going to therapy three times a week and to a psychiatrist.
'I truly believe this conservatorship is abusive. I don't feel like I can live a full life. In the meantime, I want this therapist to come to my home, I'm not willing to go to Westlake ... They set me up by sending me to the most exposed places. I need your help.
'My dad and anyone involved in this conservatorship, including my management … they should be in jail.'
Since then, the singer has made no secret of her wish to have more children.
In a topless beach photo from Sam Asghari's birthday vacation, Britney captioned the post: 'Planning on having babies in Polynesia !!!!!!'