The Will & Grace star is now on tour with her band, Nancy and Beth, with actress/writer Stephanie Hunt

Megan Mullally is known for her award-winning acting roles but the star insists singing is her first true love.

“People are always flabbergasted, like ‘You sing?’” Mullally tells PEOPLE in this week’s issue. “Nobody knows I sing. Even though I’ve done Broadway musicals. I would only pick it over acting because it’s such a pure form of emotional expression.”

Now Mullally, 58, has a new album with her band, Nancy and Beth, that she formed with actress/writer Stephanie Hunt. The women sing every song in harmony and their sound is “punk vaudeville,” Mullally adds. “It’s everything from super hillbilly to Rufus Wainwright. There’s a rap song, a couple of songs from the ’50s, you name it, all different genres and eras. And it all goes together somehow really well.”

Mullally and Hunt became friends after working together on the 2012 indie film, Somebody Up There Likes Me. “We really hit it off,” Mullally says. “We just have a real affinity for each other and we like a lot of the same things. We have very similar tastes in music. Beyond that, we have that weird psychic connection like I do with Sean Hayes where we just read each other on stage. As a performing duo, it’s fantastic.”

The two are taking their talents on tour in April and May and will play in various venues across the United States and in Europe as well. Their live show “is so much fun,” Mullally adds. “Every song is choreographed but it’s all tongue and cheek, we don’t take anything too seriously. It’s not a scripted show, it’s a band. There are all sorts of fun surprises.”

For their album cover, Mullally and Hunt decided to bare all and go naked. “We wanted to present ourselves as simply two humans on the planet,” she says. “Stephanie and I have such a simpatico in so many ways, but we never realized we were so physically similar till we shot this cover. We didn’t realize we were exactly the same proportions.” The two also just released the video for their first single, “Please Mr. Jailer.”

Despite her busy tour schedule, Mullally says she’s looking forward to returning to her role as Karen Walker on NBC’s Will & Grace later this year. The show got a 10-episode revival after the cast filmed an election video last fall. “I was floored,” the actress says of the overwhelming response to the video. “I just couldn’t believe it, so many people want the show back.”

Reuniting with the show’s whole crew “is exciting,” Mullally adds. “I’m considering that my vacation because I’m so busy until then. I’ll be able to relax with my friends and have fun.”

In the meantime, she’ll get to share her passion for music with fans around the world. “I can’t tell you how much the audiences love it,” she says. “That’s all you ever want — to do your job well enough that people on the other end are happy.”