The track is the first to be taken from his forthcoming album Take The Crown and was co-written by his Take That bandmate Gary Barlow. The pair previously worked on Williams's single 'Shame', which was released in 2010.
"It's a summer song about a girl who thinks she's great," explained the 38-year-old singer on his official website. "And she might be, but she's a bit nefarious with her ways.
"Some songs take an age to write and some songs just fall out of your mouth completely formed, and you don't have to think about it. I don't know why that fell out of my mouth and out of my brain at that particular time - it just did."
Williams also confirmed that 'Candy' will receive its first radio play on Monday, September 10 at 8am (BST). He is expected to appear on a number of UK breakfast shows throughout the morning to promote the song.
'Candy' is scheduled for release on October 29, with Take The Crown following on November 5. Williams has said that the album is "full of worldwide hits" and recently announced that he would be playing a series of gigs to promote the record.
Williams was awarded an 'Icon' accolade at the GQ 'Men of the Year' awards last week.
He was spotted filming the video for 'Candy' in Spitalfields, East London last month.