Mila Kunis and Ashton Kutcher are planning a romantic break on a riverboat.

The 'Two and a Half Men' actor booked the floating accommodation on the Norfolk Broads, east England, while his girlfriend shoots her new film 'Jupiter Ascending' nearby as he believes it will be a unique experience for the couple during their stay in the UK.

A source told The Sun newspaper: ''Ashton thinks it will be a great experience. They've got no qualms about staying on a boat. They won't exactly be roughing it.''

Ashton, 35, initially flew overseas to spend time with Mila, 29, as he was missing her during her busy work schedule and the pair have temporarily moved into a luxury apartment in Hampstead, North London.

However, it was recently discovered that the idyllic location is also a 'dogging' hotspot, where people gather to embark on public sex.

A source revealed: ''Mila has come over to London ahead of Ashton to start shooting.

''Ashton has a bit of time between projects so has decided to relocate to London and house-sit while Mila is at work. They originally planned to move more central to Marylebone but she fell in love with Hampstead when she had a day off there with some friends.

''The apartment they have is opposite a notorious car park on the heath which is well documented on the internet as a site for voyeurs seeking thrills with strangers.''

Since Ashton jetted out to London the couple have been spotted out on several outings - including attending an opera at the Barbican - and had a narrow miss with Mila's ex-boyfriend of eight years Macaulay Culkin, who is also in town.