The '...Baby One More Time' hitmaker tweeted: "'Matches' featuring my friends @backstreetboys is out now!!!!

"I'm so excited to hear what you think about our song together!!!! You can also listen to Glory Deluxe everywhere now!"

As per the 'Larger Than Life' group, the track was two decades in the making.

They added: "What a GLORIOUS day it is... we've been asked about the possibility of a collab like this for the past 20 years and today is the day!! #BritneyXBackstreet is finally here! #Matches is out now on @britneyspears' Glory Deluxehttps://smarturl.it/xMatches (sic)"

Last week, Britney released a never-heard-before song from 'Glory', 'Swimming In The Stars', to mark her 39th birthday (02.12.20).

The new music comes after it was revealed that Britney "will not perform" whilst her father is her conservator.

The 'I'm a Slave 4 U' hitmaker - whose last gig was in October 2018 - recently filed new documents via her lawyer which asked the courts to strip her father, Jamie Spears, from his position as co-conservator of her estate entirely, as she no longer wants him in control of her life and career.

And last month, her lawyer claimed Britney is "afraid" of her dad, and doesn't want to step foot on stage until he has been ousted from his role as conservator.

During a court hearing on November 10, Samuel D. Ingham III said: "My client has informed me that she is afraid of her father. She also stated that she will not perform as long as her father is in charge of her career. We are really at a crossroads."

The court hearing was held to determine whether Jamie will remain the co-conservator of Britney's estate, but Judge Brenda Penny ultimately decided not to suspend Jamie, although she said the matter can be further discussed "down the road."

Despite her legal battle with her father, Britney - whose fans have launched the #FreeBritney campaign - recently admitted she is "happiest" she's ever been.

Upon her return to social media after a brief break, the Grammy-winner told her fans she is "fine" and in a great place personally.

In a video for her followers, she said: "Hi, so I know that there have been a lot of comments, and a lot of people saying a lot of different things about me.

"But I just want to let you guys know that I am fine. I'm the happiest I've ever been in my life.

"And I'm sending all of you guys a lot of prayers, wishes and a lot of love."