The Smash star took to Twitter on Saturday (24Sep16) to announce the happy news.

"#pregnancyannouncement," the 35-year-old captioned a photo of herself wearing a T-shirt that reads: "Eating for Two."

Megan's husband, musician Brian Gallagher, is also in the picture, wearing a shirt which reads: "Drinking for Two."

Following the pregnancy announcement, many of Megan's famous friends, including pregnant Broadway stars Audra MCDonald and Laura Benanti, congratulated the actress.

"Awww snap! Our play dates are gonna be lit!" Audra wrote. "Right @LauraBenanti? Congrats Mama!!!!"

"#BestFriendsForever whether they like it or not!" Laura wrote.

Megan was happy about the idea of the theatre stars' children being raised together, writing, "Is it too soon to come up with a name for the kids' singing group? It's too soon, right?"

Megan and Brian are already parents to two-year-old daughter Viola Philomena. The couple wed in Las Vegas in 2013.

Meanwhile, Hilty will be keeping busy with her role in the First Wives Club TV series, in which she will star alongside Alyson Hannigan and Vanessa Lachey, who announced her third pregnancy earlier this month (Sep16). The reboot will be based on the 1996 movie, which featured Diane Keaton, Bette Midler, and Goldie Hawn as dumped wives. The series was picked up by bosses at America's TV Land in March (16), but it is unclear when it will premiere.

In the movie, adapted from author Olivia Goldsmith's book of the same name, the three women reunite for their college friend's funeral and make a pact to seek revenge on each of their ex-husbands.

The television version will take be set in modern-day San Francisco, California.