At the time, Hayden was over 10 years younger than Milo, and they reportedly split over "lifestyle conflicts" in 2009.Chad Michael Murray and Sophia Bush met on the set of One Tree Hill in 2003 and tied the knot in 2005 after dating for two years.
They stayed together for two-and-a-half years before divorcing, and Jennifer went on to date her Alias co-star Michael Vartan. Rachel went on to date Hayden Christensen, while Adam has reportedly found love with another TV darling, Leighton Meester.
Before tying the knot with Ryan Reynolds in 2012, Blake Lively was coupled up with her Gossip Girl co-star Penn Badgley.
It was there that she met and began dating her co-star Michael Weatherly.
The two were engaged in 2001 but ended their relationship in 2003.
Gossip Girl co-stars Leighton Meester and Sebastian Stan dated for two years before calling it quits in 2010.