Catherine Zeta Jones hid her struggle with depression
The 41-year-old beauty recently underwent treatment for Bipolar II disorder - which was triggered by her 66-year-old husband`s battle with throat cancer - but the `Wall Street: Money Never Sleeps` actor says his wife managed to conceal this condition from him for a long time before she sought help.
He said: "It`s hard for your wife to say `I`m depressed`, you know.
"It`s probably been going on for a while. But I wasn`t really aware of it. You know Catherine and Brits in general - Catherine is Welsh, you never see them in a bad spirits right? They always give the stiff upper lip, carry on and this and that.
"I`m really proud of her. There are some great medications out there now for people, it`s an issue that affects a lot of people."
While Catherine has now returned to work, Michael - who was given the all-clear from cancer in January following six months of chemotherapy and radiotherapy treatment - admitted their children Dylan, 10, and eight-year-old Carys do not know about their mother`s condition because it came so soon after their father`s illness.
He said on US TV talk show `The View`: "No, they don`t know yet. We gotta give them a chance, they`re just getting over the other issues.
"Of course the hardest part is not the kids at the school, it`s the parents of the kids, you never know how much they`re sharing with their children."
Michael has had a tumultuous year in which he has seen eldest son Cameron imprisoned on drugs charges and his ex-wife Diandra launch legal action in a bid to gain a percentage of his salary from recent movie `Wall Street: Money Never Sleeps` and the actor believes his difficulties are "karma" for his previous good fortune.
He said: "It`s been a long year-and-a-half. Life had been good to me for a really, really long time and I was thinking I`m going to get hit by a truck, it`s been too good.
"So this karma in the last year and a half has kind of balanced things out, so I feel pretty good for the future."
"I joke about it but in the last year-and-a-half my oldest son got incarcerated, sent to federal prison, my ex-wife sued me, I got cancer."