Britney Spears felt "so blessed and grateful" while celebrating her 40th birthday on Thursday.

Following a turbulent year in her personal life, culminating in Judge Brenda Penny formally terminating the controversial 13-year conservatorship of the person and estate last month, the popstar took to Instagram to mark turning the milestone age.

"I'm so blessed and grateful!!!! Tears of joy today...Thank you for all the b-day wishes," she wrote alongside a video showing her fiancé Sam Asghari popping open a bottle of Champagne. "Psss I didn't even drink the champagne. No lie!!!!"

In the video clip, Britney also offered fans a glimpse of her birthday cake, an extravagant balloon installation, her hotel in Cabo San Lucas, Mexico, and a firework display on the beach.

And in his own message, Sam praised his fiancée and hinted they may tie the knot sooner rather than later.

The Toxic hitmaker and actor got engaged in September, after five years of dating.

"I call you Lioness because I admire your relentless strength, I'm inspired by your beautiful heart, I celebrate your smile that lights up my world. Every day is your birthday my queen. Happy 1st birthday to my wife," he captioned happy snaps of himself and Britney stepping onto a private jet on Wednesday.