Former Democratic presidential hopeful John Edwards has been indicted on felony charges by a federal grand jury.
A North Carolina grand jury accused him of using cash from two wealthy donors to shelter campaign aide Rielle Hunter, with whom he fathered a child.
He is accused of using $US925,000 in campaign funds to pay her living expenses and hide her from the media.
Lawyer Gregory Craig said he will plead not guilty. If convicted, Mr Edwards faces up to five years in prison and a $250,000 fine.
Mr Edwards at the time was married to Elizabeth Edwards, a figure widely admired for a courageous public fight with breast cancer.
The couple split in January 2010 after he admitted the affair and Mrs Edwards died of cancer less than a year later.
Mr Edwards, 57, a wealthy former trial lawyer, was elected to the US Senate in 1998 and served a single term.
He ran for the Democratic presidential nomination in 2004 and joined Senator John Kerry as vice-presidential candidate on the Democratic ticket.
The investigation began in early 2009.