Despite getting engaged in March the couple are said to be at the lowest point of their relationship with Sienna, 26, growing tired of 39-year-old Rhys.

A friend of the couple told 'Grazia 'magazine: "It's awful but everyone who knows them can just see it coming a mile off. Rhys seems madly in love with her still, but everyone is speculating Sienna has grown out of the relationship

The pair's troubles are said to have stemmed from hectic work schedules, Sienna has been busy shooting The Edge of Love with ex-boyfriend Matthew Rhys and is now working in LA, while Rhys has been busy working in the UK.

Another friend told 'Closer 'magazine: "Sienna promised to spend a week with Rhys. He arranged his filming schedule, but at the last minute she cancelled her trip, saying she had to work. Rhys hit the roof when he called her and found out she was partying in Los Angeles."