Justin Theroux says his relationship with Jennifer Aniston ''doesn't feel difficult''.

The 42-year-old actor is engaged to the 'Friends' actress and admits that he doesn't understand reports that say they don't have a smooth relationship because of the time they spend apart.

He said: ''It doesn't feel like a hardship, it doesn't feel difficult.''

'The Leftovers' star can't understand why people are so desperate to know about their relationship and thinks it's bizarre that paparazzi are willing to do anything to get a picture of them together.

Justin told the latest issue of Details magazine: ''It can be an annoyance, but it's not the end of the world.

''You have to centre on what its core thing is, which is that you met someone you fell in love with. It's hard to explain. I just find myself wondering, 'What's the big f**king deal?''

Justin - who met Jennifer on the set of their 2012 film 'Wanderlust' - also revealed that he feels as though he's better off not speaking about their relationship at all because what's printed is ''always based on fiction''.

He continued: ''You just kind of ignore it but then you also become reluctant to say anything about the relationship.

''I could say, 'Everything's good', and then it's reflected back as, 'JUSTIN THEROUX: EVERYTHING'S GOOD?' That just creates this echo chamber, and it ricochets around the internet, it just gets wacky.''