Hailee Steinfield rocked a sophisticated ensemble to the bash.
The screen starlet had the important job of handing girl group Fifth Harmony the Group of The Year honour.
Lana Del Rey was handed the Trailblazer award at the event.
The 'Born To Die' singer picked up her award in a stunning black embroidered jacket and was handed her prize by Pete Wentz.
Ciara looked smoking hot at the Billboard bash.
The 30-year-old beauty looked super-sultry in a black dress giving a rather leggy display and showing off her ample assets.
Demi Lovato rocked up to the Billboard party in a revealing trouser suit, showing off her impressive bust - which was further accentuated by her lack of a bra or top.
Her sexy outfit ensured all eyes turned to see Demi as she stepped inside.
Pete Wentz wasn't the only male music star in the building.
Tony Bennett supported his 'Cheek to Cheek' collaborator Lady Gaga and was seen clapping loudly when she stepped up to accept the prestigious Woman of the Year prize.
The Billboard Women in Music event didn't only honour modern female musicians.
Loretta Lynn was crowned a bona fide Legend at the star-studded ceremony.
The 83-year-old singer looked half her age as she stepped out of a blacked out car in a flowery p...
And this year's Group of The Year were Fifth Harmony.
The girls strutted their stuff in on the red carpet with each member showcasing their own unique style at the Billboard Women in Music bash.
Isabella Lindblom flashed her right side in a revealing black gown at Rihanna's Diamond Ball.
The blonde beauty looked like she had no knickers underneath the raunchy ensemble!
Emily Ratajkowski rocked an off the shoulder gown on the red carpet at the star-studded bash.
The 24-year-old model showed off her long pins in the simple but sexy gown, but looked rather demure.