Click on photos for gallery
"I can confirm that Jude Law and Sienna Miller are no longer in a relationship," a spokesperson said on Wednesday.
It is understood they called it a day several weeks ago, despite having just bought a £8million London home two months ago.
A source told US publication People that the split was amicable, and that the couple remain friends.
"It was entirely an end-of-the relationship decision," says the insider. "It had run its course."
Jude and Sienna first laid eyes on each other on the set of Alfie in 2003. The attraction was instant and by the time filming ended, they were a couple in real life.
They got engaged on Christmas Day the following year but split in 2006 after Jude admitted being unfaithful with his children's nanny.
After the break up Sienna went on to date Welsh actor Rhys Ivans. She also had a short romance with US actor and dad-of-four Balthazar Getty, who has since gone back to his wife.
Jude, meanwhile, fathered a child with US actress and model Samantha Burke after dating her very briefly while he was filming Sherlock Holmes in New York.
Their daughter Sophia - who made her debut in HELLO! magazine - was born in September 2009.
Shortly after the actor and his former fiancée reconciled when they were both starring in separate Broadway plays.
They enjoyed a New Year break in the Caribbean, and made their first public appearance together again at the Costume Institute Ball in May 2010.
And after they set up home together, celeb watchers were certain a wedding would soon follow. There were even rumours Sienna had asked her sister Sienna to design a wedding dress.
But this was one Hollywood sequel that didn't go the distance.