Kutcher, 34, and Kunis, 29, are already househunting in the flash Marylebone area, where their neighbours will include Hollywood beauty Kate Hudson and filmmaker Guy Ritchie, reported Sun online.
"Mila is over for at least six months filming near London and Ashton has decided to head here too. They spend most of their time glued to each other's side," a source said.
Kutcher has finished work on his biopic of Apple founder Steve Jobs. It also takes him away from the US, where his messy divorce from Demi Moore is being finalised.
Kunis begins shooting 'Jupiter Ascending' with the Wachowski brothers this Spring. In the film, she plays a Russian immigrant. The 'Ted' star is so committed to the part that she is having lessons so she can pick up the right accent.