"She's a little more than three months along and starting to show," a source tells US Weekly.
"It was totally unexpected, but they are incredibly happy and excited."
According to the report, Heather and Taylor have no plans to wed—yet.
However, ""I see it in their future," says the source.
Here's to a bright and happy future for both!
How cool of a mom do you think Heather will be? Tell us in the comments below or on Twitter @OKMagazine
For access to all our exclusive celebrity videos and interviews – Subscribe on YouTube!