The Mortal Instruments: City of Bones costars Jamie Campbell Bower and Lily Collins have broken up after a year of dating. Credit: Ian Gavan/Getty Images

Lily Collins and Jamie Campbell Bower have recently broken up, sources tell Us Weekly exclusively. The actors, both 24, were first romantically linked in July 2012 while shooting The Mortal Instruments: City of Bones in Toronto, Canada. "They remain very good friends," an insider says.

In preparation for the supernatural film's Aug. 21 release, the exes have been on a nationwide press tour that included mall appearances, television interviews and more. "They've been really good about doing the press tour together for their movie," a source explains of the professional pair. "They were able to stay friendly."

Collins previously dated her Abduction costar Taylor Lautner from November 2010 to September 2011; she also romanced Zac Efron for three months in 2012. Campbell Bower, meanwhile, was previously engaged to his Harry Potter and the Deathly Hallows: Part 1 costar Bonnie Wright. They quietly split in June 2012 after two years together.