Sophia Bush's divorce from Chad Michael Murray was ''unpleasant''.

The 'Chicago PD' star, who split from the 32-year-old actor after five months of marriage in September 2005 following rumours he cheated on her with Paris Hilton, hasn't remained friends with her ex-husband despite continuing to film the series 'One Tree Hill' alongside him until 2012.

Asked if they have stayed in touch, the brunette beauty told 'Watch What Happens Live' with Andy Cohen on Monday night (06.01.14): ''That's such an interesting question. But my mother once said to me that if you don't have anything nice to say, not to say anything at all.''

The former couple originally filed for an annulment but were granted a divorce in December 2006.

Sophia, 31, claimed she and Chad ''had no business'' being together but working with him helped her move on from their split.

She said: ''At the end of the day we're grownups, and I actually think what's interesting about it is that when people split in a way that's unpleasant, they usually just go on quite literally hating each other - or the person in my situation hates the other person, whatever - but when you have to work with somebody for another half a decade, you kind of have to deal with it. Because for me, at the end of the day, my job is my priority. And so I think at the end of it, it really let me just let go of it.''