The Vampire Diaries star shared the happy news on Instagram earlier today (August 31), posing with her husband - The Fray member Joe King - and step-daughters in the sweet family picture.
The foursome can be seen posing in white T-shirts decorated in colourful paint, with Accola's shirt saying "baby" and King's saying "Superdad".
"Sometimes a Saturday is best spent painting T-shirts and taking an awesome family photo," Accola wrote. "Happy Monday everybody! #ThatAintNoBurritoinMyBelly..."
The baby will be Accola's first, while King has two daughters from a previous marriage.
The pair tied the knot back in October 2014, after announcing their engagement in May 2013.
Accola appears as Caroline Forbes on The Vampire Diaries, which returns to The CW for a seventh season later this year.
