Kutcher, 32, and his No Strings Attached co-star Natalie Portman, 29, opened up about why it's not that uncomfortable for their significant others to watch their love scenes in their new flick.
Ashton, who has been married to Demi Moore for more than five years, told Etonline.com: 'The great thing is that we're both in the same profession, so we know exactly what goes on in those days.
'And we know how technical it is and how it's not really all it's hyped up to be - it's movie magic.'
While a pregnant Natalie insisted that her fiancé Benjamin Millepied is secure enough in their relationship to not be bothered when he sees her on-screen with someone else.
She added: 'He knows who I love.'
In the film Natalie plays a woman who tries to have a sexual relationship with a male friend without getting romantically attached.