The Private Practice actress stars as Amelia Shepherd in the Shonda Rhimes series, the sister of Grey's Anatomy's Derek Shepherd (Patrick Dempsey).
Speaking about having her first child, she told People: "We're over the moon. I'm starting to show now. Everybody on set has been pretty sweet and is offering me fruit."
She added that her character will soon also become pregnant in Private Practice, revealing: "This year Amelia, who had been sober, fell off the wagon after her friend died. She hit rock bottom, had an intervention and went to rehab. So this news is on the heels of that."
Scorsone explained that Rhimes decided to use her real life pregnancy for a dramatic new storyline, saying: "The news came out of left field and I think she decided she could use this for dramatic purposes.
"As an actress it never feels like the right time. But once we knew what was happening we were like, 'This is perfect.'
"Shonda was immediately excited and talked about what we could do when the baby came so [he or she] could be on set. She's been unbelievably supportive."
Rob Giles's music with The Rescues has featured in several episodes of Grey's Anatomy and Private Practice, while he has also worked with its stars Kevin McKidd and Sara Ramirez.