The birth of Kate Hudson and Chris Robinson's son Ryder left the former couple convinced their marriage needed help.

The pair sealed the end of their seven-year union with a divorce in October, and now Hudson has revealed her son Ryder's birth in January 2004 was the beginning of the end.

She says, "We had Ryder, and we both sort of looked at each other and went, 'Something's off.'"

But Hudson insists she and the Black Crowes rocker are still close, adding, "(Divorce was) the most difficult thing I've ever done in my life. The process of discovering with somebody that you love that you don't...work is so painful. And thank goodness I did it with Chris… We helped each other through it.

"Now we're both single and since the day we separated, we talk multiple times."