Singer Rihanna arrives for the Council of Fashion Designers of America Awards.Reuters

Rihanna had all eyes on her, as she looked stunning in a red floor-length gown, at her first annual Diamond Ball in Los Angeles. The dress, which was designed by Zac Posen, accentuated the singer's breasts. She exhibited cleavage and accessorised her look with Chopard jewellery.

According to OK magazine, she has undergone plastic surgery to enhance her breasts and this was the reason she wore a cleavage-baring gown for the ball. It was previously reported by the magazine that the singer is unhappy with her breasts and is considering a surgery.

"Rihanna feels like her boobs are starting to droop because she rarely wears a bra," a source told the magazine. But, there is no confirmation to the report yet.

Meanwhile, Kim Kardashian and actress Salma Hayek also attended the Diamond Ball. "The Fury" star Brad Pitt was at the event to introduce Rihanna. He announced her as the founder of the event with a speech and accompanied it with some childhood pictures of the singer.

The Ball was organised for the benefit of Rihanna's Clara Lionel Foundation. This is a charity founded by the singer in honour of her grandparents, Clara and Lionel Brathwaite.

The money raised from the ball will be used to assist Clara Brathwaite Centre for Oncology and Nuclear Medicine at the Queen Elizabeth Hospital in Barbados. RiRi has been working towards improvement of the cancer facilities in the Caribbean Island since loosing her grandmother to the fatal disease.

In other news, she is currently busy with her eighth studio album called "R8." She recently released a 15-second song teaser of the album on her Instagram account. The new song is titled "Kiss It Better", which will be Rihanna's first album in the last two years.