The 38-year-old actress gave birth to son Joshua Bishop, her first biological child, with husband Josh Kelley on 20 December (16). The baby boy makes his public debut on the cover of this week's (beg23Jan17) People magazine, with Katherine opening up about how her life has changed with her new arrival.

Even with three kids, the former Grey's Anatomy star would definitely consider adding to her brood in one way or another.

“I’d get pregnant again, and I still am very inspired by adoption. I also have been thinking a lot about fostering. It’s all up in the air,” she told the publication of expanding her family. "And I’m okay with that!"

Katherine also recalled how much of a shock it was when she discovered her pregnancy and the timing wasn't the best either, as the actress had just returned to work on new CBS show Doubt.

"I’ll be totally honest, my first reaction was ‘Oh s**t,’” she laughed. "But now we have a new normal, and I have to give myself a break in order to get used to it."

Katherine and Josh are already parents to eight-year-old Naleigh, who they adopted from South Korea in 2009, and four-year-old Adalaide, who they adopted from Louisiana in 2012.

Having explored adoption on two previous occasions, Katherine admits carrying a baby herself wasn't something that really worried her - until she started getting older.

"(Being pregnant) didn’t ever really speak to me. I got really invested in adoption. I didn’t look back or even think about it,” she said. “Only when I was about 35 did I start going, ‘Well, should we consider getting pregnant?’ You don’t want the choice to be taken away from you."

Katherine will be returning to work next month (Feb17) to promote Doubt. But in the meantime, she is making the most of every second with her newborn.

"We’re at the point where we’re really obsessed with him!" she smiled. "With a newborn, you’re forced to be still... and you have this beautiful reason to do that."