The female lead in director John Carney's indie hit Sing Street has been cast as Freddie Mercury's longtime lover in Bohemian Rhapsody. Following the casting in July of Rami Malek as Freddie Mercury in the biopic about the legendary rock group Queen, director Bryan Singer has been steadily building up the film's cast.

Last month, Singer filled out the rest of the band, including Gwilym Lee as guitarist Brian May, as well as Ben Hardy as drummer Roger Taylor, and Joe Mazzello as bassist John Deacon; and last week, the director cast Allen Leech (Downton Abbey) to play Mercury's longtime personal manager Paul Prenter.

According to THR, Singer has tapped Lucy Boynton, who also has a supporting role in the upcoming mystery thriller Murder on the Orient Express, to play Mercury's longtime companion Mary Austin. THR says the pair were in a relationship and lived together for several years, but broke things off when Mercury revealed to Austin that he had affairs with male lovers. The Queen frontman and Austin remained friends for the rest of Mercury's life, and he reportedly left of the vast majority of his wealth to her.

Related: Rami Malek is Freddie Mercury in Bohemian Rhapsody First Look Image

Sing Street cast walking down the street.

It's hard to tell at this point just how prominent a part Austin will be to the overall narrative of Bohemian Rhapsody, which will chronicle Mercury and Queen's rise to fame from 1970 through the band's classic performance at Live Aid in London in 1985.

Austin was no doubt an inspiration to Mercury in real life, penning several tunes for her including the heartfelt ballad "Love of My Life," from the band's iconic 1975 album A Night at the Opera (which also included the band's monster hit "Bohemian Rhapsody"). With Austin's role in Mercury's life being a part of Singer's film, it virtually guarantees that "Love of My Life" will be one of the Queen songs in the film, and a vital contribution to what is sure to be an impressive soundtrack.

Singer has to be commended for all of his casting choices to date, picking solid actors for the roles over bigger name celebrities in what is surely going to be a film that will attract a lot of buzz as it heads into theaters Christmas Day in 2018. Boyton, who showed an incredible amount of presence in Sing Street seems to be a natural for the role, especially given that played the female lead in music-centric film already.

Anyone who's seen Sing Street – Carney's under-appreciated musical chronicles the plight of a pop band of high school misfits in 1980s Dublin – knows that the film was one of 2016's most pleasant surprises and signaled a bright future for Boynton. Oddly, enough, Boyton also played the muse to the band's founder (Ferdia Walsh-Peelo) in Sing Street, making her seem almost destined to play the woman that illuminated Mercury.

NEXT: Bohemian Rhapsody Casts the Other Members of Queen

Source: THR

Key Release Dates