The thrilled couple took to Instagram to break the news.
The 26-year-old "Big Time Rush" actor shared a happy picture of himself with Vega.
"Breaking news!It's #ClearblueConfirmed! There is going to be a new cool kid in town...And by cool I mean dorky just like their father. A little PenaVega is on the way! Its Happening #HolyWow #Imgoingtobeadaddy #clearbluepartner," he captioned the photo.
Pena and the "Spy Kids" star got married in 2014.
"I cannot believe I finally get to say this... WE'RE PREGNANT! It's #ClearblueConfirmed that a little blessing is joining the PenaVega family! We can't wait! #ItsHappening #HolyWow #LosForDaddyOfTheYear #ClearbluePartner," Vega, 27, posted.