The duo was also snapped snogging at the wrap party for Kutcher’s latest film, a biopic of Apple genius Steve Jobs, at the weekend.
“They’re basically living together. Like any new couple in love, they’re pretty much joined at the hip,” the Sun quoted a source as saying.
“They’ve been sneaking around for months but there’s only so long you can keep it quiet.
“They’re staying with each other most nights. Mila’s practically moved in to Ashton’s Hollywood home,” the source added.