Robbie Schloss and Kirsten Barrish Schloss said they were seated near the actor during last week's Game 3 of the National League Division Series and ended up talking with the star, who sang "Take Me Out to the Ball Game" during the 7th inning stretch.
The couple said their chat led to Murray helping them record a video to tell their parents about their pregnancy.
"Hey, I've got news for you. You're going to be grandparents," Murray says in the video, which the couple posted to Instagram.
"We're having a baby!" Schloss chimes in when Murray points to him.
The couple said they had been trying to get pregnant for a few years and weren't planning to make a social media announcement, but they couldn't resist the opportunity of getting Murray to help.