Recent reports claimed Tricia and the Grammy Award-winning rapper were expecting a child, and the 'Thrift Shop' star has taken to Twitter to confirm the news.
Alongside a touching video, Macklemore tweeted: "We wanted to share the news with you ourselves."
In the video, the 31-year-old star can be seen holding hands with Tricia - a former nurse - as they look at 3D ultrasounds and the heartbeat of their unborn child.
The couple, who have been dating for nine years and have been engaged since January 2013, have yet to set a date for their wedding.
And in a recent interview, the rapper joked that their wedding is likely to be a few years away still.
Macklemore told US radio station Hot 97: "I've been sluffing.
"I'm a rapper so I propose and then like seven years later we'll finally tie the knot. But we bought a house and live together so we're basically married."
In addition to the birth of his first child, 2015 will also see the release of Macklemore's much-anticipated third studio album.