According to court documents exclusively obtained by Radar, Will's 43-year-old brother, Carl Gilliam, was arrested in 2005 for a domestic incident with his now ex, Toni Mahome, in which he was charged with three counts including: maliciously disfiguring or disabling another person's body (maiming), assault with a deadly weapon and corporal injury on a spouse.
Arrested by the Los Angeles Police Department, Gilliam appeared in front of Judge David Mintz on Feb. 2, 2006 where he pleaded not guilty to all three charges.
His bail was set at $500,000.
That same month Gilliam took a plea deal allowing the first two counts to be dismissed, leaving him with a guilty plea on the third count.
On March 24, 2006, Gilliam was sentenced to five years in a state prison, court fees and a $400 domestic violence fine.
Gilliam's arrest came at the height of The Black Eyed Peas' fame, just days after their second hit album "Elephunk" featuring hits like "Boom Boom Pow" and "My Humps" was released.
An insider tells Radar that Gilliam and the victim, Mahome, have children together but are no longer involved with each other.
"He's not a good guy," the source said.
But the Black Eyed Peas frontman seems to think the opposite of his brother.
In 2010 when will.i.am threw out the inaugural pitch at the LA Dodgers season opener, it was his brother Carl that was by his side giving him pointers.
And in 2012 Will gave an interview to The Telegraph in the UK where he was quoted boasting about his brother and attributing his work ethic to him.
"From having a very stylish older brother, who always made fun of me when I was little," he said.
"Carl is five years older – a shoe designer and a stylist – and I still look up to him. He is cool."
Will has never met his father and was raised by his single mother who had three boys, a girl, two adopted boys and two adopted girls.
Radar reached out to Mahome directly and Gilliam's legal council, but both had no comment.