The 23-year-old posted her happy news on her official website, calling it a 'first anniversary announcement' as it's exactly a year since she tied the knot with husband, and now dad-to-be, Mike Comrie.
The post from the actress and singer read:
'Hello everyone! This weekend, Mike and I are celebrating our 1 year anniversary! In memory of the special day, we decided to post some of our favorite pictures from our wedding!
'I can't believe it has already been a year, time really flies when you're having fun! We also want to share the exciting news that BABY MAKES THREE!!! We are extremely happy and ready to start this new chapter of our lives. Thanks to everyone for the continued love and support throughout the years.'
At 23, Hilary, who shot to fame playing the title role in Disney's Lizzie McGuire, is set to join these other famous mums and dads who welcomed children in their early 20s....