"Platinum is my hair color, my wedding ring, the color of my Airstream and the name of one of my favorite beers," she said in a press release Monday.
She described the 16-song collection as having humor, nostalgia and "girl power." Add double trouble to the mix when two of country's leading female vocalists – Lambert and Carrie Underwood – belly up to the party bar for "Somethin' Bad." The two debuted the song at the Billboard Music Awards May 18.
"To me, this is such a big deal that Carrie and I are singing together," Lambert, 30, tells PEOPLE Country. "It took me forever to write the email to ask her, like I was writing to someone I had a crush on and you don't want to mess it up."
Radio silence on the Underwood front made the wait worse – but it turns out the American Idol winner was just mulling the offer.
"It took a week for her to get back to me and I was telling [husband] Blake, 'She hates me, she hates the song, she's never going to talk to me again, she's probably going to change her email address!' " Lambert jokes to PEOPLE. "She finally wrote me back and said, 'I think it's awesome, let's do it!' "
The musician continues, "When she came in the studio I was writing to Blake, 'I'm in over my head, I don't know what I've done!' When you respect someone like that you get so nervous. To hit the notes she hits, I would have to take off running and jump as high as I could."
However, the pairing works. "This song meshes our styles – it's a great match of what she does and what I do," Lambert explains. "I hope she'll come to the dark side and we can explode something on video! I want the 'Before He Cheats' Carrie!"
Lambert will perform the first single from the album, "Automatic", on the ACM Awards, airing live from Las Vegas April 6 on CBS.
Lambert has seven nominations and hubby Shelton will co-host again with his bromantic buddy Luke Bryan.
For more on Miranda Lambert and all your favorite country stars, pick up the latest issue of PEOPLE Country, on newsstands March 28