The actress, 39, who plays character Olivia Pope in the popular drama, revealed the happy news on the red carpet at the 2016 Met Gala in New York City, posing and smiling for photographers as she cradled her bump.
Kerry, who is also known for her roles in feature films such as Django Unchained, Save the Last Dance, and Ray, chose a dramatic black dress for the occasion, and showed off a new plum-tinted hairdo as she entered the event.
Kerry looked happy and relaxed as she placed a hand on her growing stomach
Already mum to three-year-old Isabelle Amarachi with husband Nnamdi Asomugha, a former football star, Kerry has previously said that motherhood made her feel 'very lucky'.
'You know it [motherhood] just turns your world upside down in the most beautiful way. She makes me better, I hope, every day. I feel very lucky to be her mum,' she said.
She added that she'd asked lots of other celebrity mums for advice along the way.
'I called up Connie Britton, who adopted her son when she started [TV show] Nashville. I emailed Jessica Alba. I have all these girls I have known for a long time. Now we have a new chapter in our lives we can share ideas about.'
'I will say I feel really, really blessed. I just feel really blessed that I'm kind of living extraordinary dreams come true in my work life and in my personal life.'
Kerry and Nnamdi tied the knot in secret in 2013 and welcomed Isabelle into the world in April 2014. No word yet on when the new arrival is due, or whether the pair are expecting a boy or a girl, but we already can't wait to see what baby name they choose...