The 17-year-old One Direction heart-throb had arrived at 32-year-old Caroline's house at 10pm on Monday carrying his overnight bag.
The Xtra Factor presenter had been out earlier buying food and wine for what appeared to be a romantic evening in with her toyboy love.
And when Harry emerged at 9.30am yesterday he looked tired and dishevelled ? with his hair even more ruffled than usual.
Caroline came out of her home in Muswell Hill, North London, two hours later in dark sunglasses, tight plum trousers, high heels, carrying a big brimmed hat and wearing a broad smile.
She and Harry ? whose group came third on X Factor last year and are in the album charts with debut Up All Night ? have been on a string of dates in the past month. Caroline insists she has no worries despite the 15-year age gap.
She said recently: "I keep thinking, 'What have I done wrong?' But I haven't done anything wrong. What's hard for me to get my head around is people saying it's disgusting. I don't think it is."
Caroline added: "If two people like each other and get on, why does anyone else find a negative in it?
"I know it's human nature to gossip. But why say it's bad? No one's being hurt."
Caroline has also received hate mail from One Direction fans. But she says it does not worry her.On night out ... Caroline Flack and Harry StylesTwitter/ Xposure She went on: "It's a form of bullying. I knew they were just a minority of One Direction fans and all very young. I can't take it seriously."