During the awards show, he took the stage with Tatiana Maslany to present Outstanding Actress In A Drama Series to Elisabeth Moss for The Handmaid's Tale.
Twitter users were delighted by the pictures, taking them as confirmation of a pregnancy.
Its series finale averaged nearly 10 million viewers (live same day), which made that episode the most-watched series finale in Disney Channel's history.
The series won "Outstanding Children's Program" at the 61st Primetime Emmy Awards in 2009.
Hilarie's former One Tree Hill co-star Barbara Alyn Woods later confirmed to Us Magazine that the 35-year-old was expecting her second child with her husband, 51.
Scroll down for video The couple themselves did not officially confirm the news - although from the red carpet photos it appears Hilarie's pregnancy is advanced.
Alex and Justin have to keep magic a secret from all mortals (except Theresa), while studying to win the wizard competition, and balancing their love lives.
The rule about keeping magic a secret has been broken twice in the series by a Russo, once in season two, and once in season four.