Britney Spears could not believe it as she announced her engagement to Sam Asghari after five years of dating.

The pop-star took to her Instagram account on Sunday to share the exciting news. Sharing a video of herself and her fiancé as she flaunted a huge diamond ring, Spears wrote, "I can't f*****g believe it," adding several ring emojis and a heart. "Look at that. Do you like it?" Asghari asks her in the video, to which she excitedly yells back "Yes!"

Asghari also shared the news on his Instagram account, simply tagging his future wife alongside a picture of them kissing while a close-up of Spears' ring covered their faces. He also shared his fiancée's post on his Instagram story, writing, "A (ring sticker) to suit a real life princess (queen sticker) now a queen. We're making dreams come true one at a time!"

Congratulations have been pouring in for the happy couple since then. Asghari's manager Brandon Cohen told Entertainment Tonight that the couple are "deeply touched by the support, dedication and love expressed to them." The statement added, "Roman Malayev from NYC is the ring designer. He couldn't be more happier to be involved and make this a one of a kind ring."

The custom sparkler is a 4-carat diamond ring featuring the word "Lioness," Asghari's nickname for the "Toxic" hitmaker, engraved on the inside of the band. The 27-year-old fitness trainer, who spent months selecting the perfect design, said about the piece of jewellery, "Every designer I spoke with about the ring was amazing with great ideas, but I just clicked with Roman -- we really connected on the design and he was as excited as I was to make it special. That's why I chose him."

The engagement news comes shortly after Spears had a huge victory in her conservatorship case when her father Jamie Spears submitted his resignation from his post as her legal guardian after 13 years. A source had previously said that all of the dreams of the couple for their relationship had been on pause due to the conservatorship.

"They haven't been able to progress like a normal, adult couple. It's like dating in high school. That's been their experience for the last two years or so," the insider had said. Spears herself said in her testimony earlier this year that her legal guardians prohibited her from getting married or having another baby.

The 39-year-old shares two sons, Sean Preston, 15, and Jayden James, 14, with ex-husband Kevin Federline to whom she was married from October 2004 to July 2007. She was also previously married to her childhood friend Jason Alexander for 55 hours in January 2004.

According to court documents related to her conservatorship, she reportedly tied the knot for a third time with her former agent Jason Trawick in 2012. She started dating Asghari, her personal trainer and actor, soon after they met in October 2016 on the set of her "Slumber Party" music video in which he played her love interest.

britney spears
Britney Spears at the MTV VMAs 2015 Getty