Britney Spears shares rare photo with her kids, reveals why she hasn't posted about them in so long

Britney Spears has shared a rare photo featuring her two sons, revealing why they haven't made an appearance on her social media in so long. 

The pop star said that the speed at which her boys had grown up was "enough to bring her to her knees" in a caption alongside two family photos in which her teenage kids both donned face masks. 

"It's so crazy how time flies. My boys are so big now!" Spears wrote of Sean, 15, and Jayden, 14. 

"I know, I know... it's very hard for any mama, especially a mama with boys, seeing them grow up so fast! Talk about enough to make you go to your knees. GEEZ!" 

Spears said that she had refrained from posting pictures of her kids to her 28.5 million followers for "some time" because "they're at the age where they want to express their own identities". 

"I totally get it," she said. 

The 'Toxic' star said she felt "extremely lucky", adding: "My two babies are such gentleman and so kind that I must have done something right." 

Exactly how often Spears gets to see her children is unclear - the singer temporarily lost custody of her kids after her highly publicised breakdown in 2007, which lead to her being placed under a restrictive conservatorship helmed in part by her father. 

Spears was reportedly granted 30 percent custody of her boys in 2019, but Mark Kaplan, the lawyer representing the children's father Kevin Federline, said that the former couple had come to a "de facto" arrangement that meant that his client actually had custody for closer to 90 percent of the time. 

The 'Gimme More' hitmaker's personal life and legal struggles have been making headlines since the release of the documentary Framing Britney Spears, which examines the #FreeBritney movement, her mistreatment by the media and the fairness of her conservatorship. 

Framing Britney Spears is available to watch in New Zealand exclusively on ThreeNow