Kress, who played Freddie Benson on the Nickelodeon show, broke the news with a photo of the couple posing in front of Big Ben in London.
The pair is shown kissing each other as Kress holds Moore, who has both hands on her stomach. The humorous, emoji-filled caption is where the revelation was announced.
Kress wrote, "Me and my baby in London. 🇬🇧 Me, and my baby in London. Me. 👨 And my baby 👶 IN --->LONDON 👧🏼
He added, "Mommy and daddy are thrilled to announce Baby Kress, arriving January 2018."
The couple met on set of the 2014 movie Into the Storm, and began dating in May 2015. They tied the knot in November of that same year.
Moore was also thrilled about the news and shared a photo of her own, which was similar to Kress'.
She wrote, "I put my barf bag down for this photo."
The mother-to-be also added some extra thoughts in hashtags, writing "#seriouslySOexcited #weloveoursweetbabyKress #completelyworthit #secondtrimesterherewecome."0comments
See the photo below.
Photo Credit: Twitter / @J14Magazine