Robin Williams’ daughter Zelda wasn’t shocked when she learned her parents were heading for a divorce, insisting 18 years is a long time for any couple to be married.

The comedian’s producer wife Marsha Garces Williams filed divorce papers in March, citing irreconcilable differences for the split.

But 18-year-old Zelda admits the split had been expected "for months."

She tells People.com, "It wasn’t a complete surprise. It’s never easy to end. (But) there’s no bitterness - we’re all a family."

And she insists she isn’t too upset about the divorce, adding, "I just want my parents to be happy. And they did last 18 years - a lot longer than most!"

The Patch Adams star also has another child with Marsha, 16-year-old Cody, in addition to his grown-up son Zachary, 25, from his first marriage to Valerie Velardi.