Jude Law & Sienna Miller Split Once Again!

You can't say they didn't try, right? Jude Law and Sienna Miller have ended their relationship once again.

OK! GALLERY: JUDE & SIENNA GO GRINNING INTO THE LONDON NIGHT

The off-again, on-again couple is switched back to off now.

"Yes, I can confirm their separation," Jude's rep said (via E! News).

As for why it didn't work out this time? That remains unknown.

OK! GALLERY: JUDE LAW SUITS UP FOR PEACE IN PARIS

Jude, 38, and Sienna, 29, first starting dating back in 2004 after they filmed Alfie together... and after Jude divorced his wife, Sadie Frost.

The stars got engaged on Christmas Day of that same year. But in 2006 they called off the engagement after reports came out claiming Jude had an affair with the nanny of his children.

OK! EXCLUSIVE: SIENNA & JUDGE QUITTING LONDON FOR COUNTRY LIFE

They were brought back together when they both starred on Broadway in 2009, but it seems like that's now ran its course.