Rumours of a split began circulating in November 2015, when Kate began appearing at public engagements without her wedding ring.
At the time, a source told People magazine: 'They have been separated for a while... they have not been together for a few months.'
Blaming hectic work schedules that caused the couple to grow apart, they added that the pair were trying to stay friends: '[They] spend time together in LA when Kate is there.'
'There has been no drama... It's just not Kate's style.'
Now, almost a year after their reported separation, Len has made the news official by filing for divorce, citing 'irreconcilable differences' according to TMZ.
Reports say that Kate and Len will not be seeking spousal support from each other, which may indicate that they have a pre-nuptial agreement in place.
The couple met in 2003 on the set of Kate's hit movie Underworld, which Len directed, and tied the knot in 2004 in a romantic ceremony in Bel-Air, California.
The pair do not have children together, although Kate has a daughter, 17-year-old Lily, from her previous relationship with actor Michael Sheen.
In a 2012 interview with Parade magazine, Kate said of her relationship with her husband: 'The first time we met each other was when we were filming Underworld, and then we worked together again after we’d been married a short while, and now we’ve been married seven years, so I’ve had quite a few different experiences along the way.'
'It's different each time. We love it. I think one of the things we like least about our jobs is that it can force separation from each other.'
'One of the things that's so nice about working together is that not only do we enjoy each other professionally, but we actually get to sleep in the same bed at night and hang out with our kid on the weekends, so it's great.'