Earlier this year, Katherine Heigl and husband Josh Kelley adopted their second daughter - Adelaide - and on Thursday night, the actress explained it came as a happy surprise."This was fascinating because we started the adoption process again and we thought we were gonna adopt internationally. It's a pretty long process. It can take years," Katherine said on Thursday's "The Tonight Show with Jay Leno" of their initial plans to find a sibling for Naleigh, now 4."And then we started exploring because we had heard that Korea had gotten very hard to adopt from, and China had a very, very long waiting list and I was like (taps wrist), any day now," she continued. "And so we started exploring the idea of domestic adoption - just exploring - and then my lawyer called and said, 'There's a birth mother and she's due in four weeks and she's all yours if you want her.'"Katherine said the immediacy of their adoption news came as a surprise to her husband."He thought it was gonna be a few years, and that we were gonna end up with more of like a 9-month-old or 10-month-old, and he looked at me and said, 'You're telling me in a month we're gonna have a newborn?' And I said, 'Yes. It's perfect timing, don't you think? Look we're both here, we're not working. This is great. We can spend time with her.' And it has been beautifully serendipitous and graceful, because we've gotten to spend all this wonderful time with her."Access Hollywood