People always wonder how they maintain such a solid relationship.
But the reason seemed obvious as Naomi Watts - who has filmed all her scenes as Diana, Princess of Wales in the eponymous biopic - swapped sweet nothings with partner Liev Schreiber in Los Angeles on Friday.
The high-flying pair seemed to relish having the chance to spend some time with each other as they made the most of a coffee run in the well-heeled Brentwood area.
The 44-year-old English actress looked in fine figure as she padded down the street in a white jacket, star spangled top, jeans and white trainers.
Love in the Time of Cholera favourite Liev meanwhile was his usual macho self in a navy T-shirt, baseball cap, jeans and hideous suede sandals.
No doubt the pair, who have two children together, will have had plenty to talk about, and they seemed to be having a great time as they enjoyed the California sunshine.
It is certainly shaping up to a busy pair for the A-listers on the work front.
Liev is appearing in four different movies in 2013, though his most notable role looks to be playing the titular role in Ray Donovan opposite veteran Jon Voight.
But it appears his partner is the one with the juiciest role of all, as she is playing the tragic Princess of Wales in forthcoming feature Diana, which is released later this year.