Roasting RiRi ... Brad Pitt attends The Inaugural Diamond Ball presented by Rihanna and The Clara Lionel Foundation. Picture: Getty Images Source: Getty Images

The Fury actor has the task of introducing Rihanna at her first annual Diamond Ball charity gala.

Instead of laying on the plaudits, Pitt instead used the opportunity to stage a mock intervention in hopes of helping “this young lady find direction and purpose.”

Rihanna arrives at her 1st Annual Diamond Bal. Picture: AP Source: AP

His spiel started by showing cute photos of Rihanna as a child in Barbados.

“I’ve often asked the very questions you yourself are asking right now — what the f*** went wrong?” he asked. “It’s not a pretty story. Like so many others, Rihanna landed on the unforgiving streets of New York at the young age of 16, and soon fell in with a bad crowd, a bad crowd led by the dubious nefarious character known as the Jay Z

“For those of you not in the know, the Jay Z was an evil impresario known for churning out hit records, and ripping insane lyrics and fresh beats,” he said.

Support ... Kim Kardashian arrives at the 1st Annual Diamond Ball. Picture: AP Source: AP

Pitt also mocked her accolades.

“Since turning the ripe age of 26, Rihanna sadly has had only 13 number one singles, only 54 million albums sold, only seven Grammys, 11 Billboard Awards,” he said. “Her resume’s even more disappointing: executive producer, fashion designer, actress, entrepreneur, philanthropist, and uh, something else … and uh, she sometimes sings.”

He then implored the crowd to help get her back on track.

“I ask that we stand together by her side and show her our support and our love and say to her the hard words, ‘Rihanna, put down that sandwich, get off your ass, and do something. Goddamn it, just do something with your life.’”

Big-name guests ... Salma Hayek arrives at the Diamond Ball. Picture: AP Source: AP

The gala was to support The Clara Lionel Foundation, a philanthropic organisation, which Rihanna founded in 2012 in honour of her grandparents, Clara and Lionel Braithwaite.

Its mission is to “promote initiatives of health, education, arts and culture on a global scale”.

The event was attended by a number of Hollywood heavyweights, including Kim Kardashian and Salma Hayek.