Matthew Alan and Camilla Luddington Expecting First Child

She’s getting her person!

British actress Camilla Luddington is expecting her first child, she revealed Wednesday on Instagram.

“I am SO excited to FINALLY share with you all news that I’ve managed to keep secret for what seems like forever now… I am pregnant!!!!!!” she wrote on the social media site. “This girl gets to be a ‘cool mom’ ha!”

In the accompanying photo, Luddington — who is best known for her role as Jo Wilson on Grey’s Anatomy — posed with a pumpkin, which was adorned with the message: “Baby arriving Spring 2017.”

“We are beyond happy,” she continued, “and I cannot wait to bring you all on this journey with me!!!! I’ll be posting progress pics as the weeks go on but for now I figured I’d post this pumpkin because come spring I’ll have a belly that size.”

The new addition’s father is Luddington’s boyfriend, actor Matthew Alan, who will star next in a recurring role in Netflix’s Thirteen Reasons Why.

Luddington also shared love for her fans — and gave props to those that “guessed right” about her pregnancy on earlier social media posts, like a video with costar Ellen Pompeo.

Luddington isn’t the only Grey’s castmember who’s pregnant: Caterina Scorsone is currently expecting her second child, her rep confirmed to PEOPLE in August.

• Reporting by JULIE JORDAN