The couple - who already have three-year-old daughter Naleigh from South Korea - have welcomed another child, but a name is not yet known.

The couple`s representative confirmed: "Yes they have adopted a baby. No further details are available at this time."

In January, 33-year-old Katherine confirmed she was talking about taking on another child with her 32-year-old husband.

She said: "Josh and I started talking about it before we were even engaged. We have talked about having biological children as well but we decided to adopt first. I`d like to adopt again."

The `Grey`s Anatomy` beauty previously claimed she felt like a "bad mother" when she first adopted Naleigh from South Korea in 2009 because she could not bond with her.

She said: "I fought incredibly hard for my daughter to accept me as mother. Her rejection almost broke my heart.

"At first I blamed myself and thought I was a bad mother. It took a while before I could admit to myself that the lack of trust had nothing to do with me."
sections: Celebrities