It's all over for Charlize Theron and Sean Penn after just a year and a half together.

The star couple seemed genuinely thrilled to have found happiness together after a number of failed relationships, so we're sad to hear things didn't work out.

Sources say Charlize was the one to break things off with the Milk actor, telling him it was over during their recent joint trip to Cannes Film Festival. 

The pair were good friends for several years before finally getting together officially in late 2013. Sean was reported to have proposed to Charlize in secret six months ago during a Christmas trip to Paris, although neither party ever confirmed this. "There's no ring, but they are committed," a friend told Us Weekly at the time.

Although Charlize has had a string of relationships with fellow actors, she has never been married. Sean, however, has tied the knot twice, once to Madonna (!) in the late Eighties and later to House of Cards actress Robin Wright, from 1996 to 2010. The pair have two children together, Dylan, aged 24, and Hopper, aged 21.

Just two months before his break-up with Charlize, Sean gushed about how exciting it was to be happy in a relationship. "53 years old plus finally beginning to figure out why you haven’t been happy in a single relationship? It could seem too late. But to run into somebody now who you care about is a much more passionate, deeper, truer and – God! – a much happier feeling," he told Esquire.

The Mystic River star even discussed the possibility of marriage, saying it would be a fresh start for him. "You say I've been married twice before, but I’ve been married under circumstances where I was less informed than I am today…So I wouldn’t even consider it a third marriage, I’d consider it a first marriage on its own terms if I got married again."

We hope he's not too gutted by the split…