Hal Sparks played Donald Davenport in the show Lab Rats, which ended its run in 2016.
Asha Sanders, who lives with Down syndrome, watches reruns of the show often.
Since Asha is such a huge fan, her sister made a plea on social media to get the attention of anyone from the cast for Asha's 18th birthday.
Her wish was granted when she received a personal happy birthday message from the Disney star.
Asha's family was in tears seeing how happy this made her.
They say all Asha has wanted for the past two Christmases was Lab Rats merchandise, which they say is impossible to find.