This was just before they started filming the Wall Street follow up Money Never Sleeps.
They embarked on the romance against the advice of co-star Michael Douglas who told them never to date someone you're filming with. "I warned them, 'Don't ever do that", but they are an item and they are having a great time," he said.
Carey is due to leave in a few days to attend the Oscars, where she is up for the Best Actress trophy. It's not known whether her 23-year-old beau will be accompanying her however – they are yet to attend a red carpet event together.