Los Angeles: Hollywood star Matt Damon is so protective about his daughters that his wife Luciana Barroso has nicknamed him 'Red Alert'.

The 40-year-old actor says that being a father has turned him into a cautious man and has landed him the nickname, reported a magazine.

"I'm probably more protective than I've ever been now that I have children. My wife's nickname for me is 'Red Alert'. I sometimes check to see if the kids are breathing," said the 'Goodwill Hunting' star.

"When it comes to parenting Stella, 10 months, Gia, 3, Isabella, 5, and Alexia, 12, I tend to be a little overprotective without trying to be a helicopter parent," Damon added.