AceShowbiz -

Britney Spears is ready to wed for the third time. Rumor has it, the "Make Me..." songstress is set to propose to her boyfriend Sam Asghari, whom she has dated since late last year after he starred in music video for her single "Slumber Party".

Sources tell OK! that Britney will buy her own engagement ring and plan to tie the knot with the 23-year-old hunk before her Las Vegas residency ends at the end of the year. "Since Sam would be spending her money, Britney is buying her own engagement ring," one source says.

The couple has reportedly planned details of the wedding. "The wedding will be butterfly-themed, and monarchs will be released when they exchange vows," the source dishes, adding, "They're choreographing their first dance, which will play out the story of how they met."

As for the guest list, the source reveals, "Britney wants to invite dancers, staffers and her entire Vegas squad, as well as family and friends." Britney's little sister Jamie Lynn Spears will reportedly host the bachelorette party in her backyard. It will be a barbecue hayride with fat-freezing spa treatments and teeth whitening, the source claims.

A rep for the 35-year-old pop star, however, denies the wedding plan report.