Tiffany Fallon isn't the only one in her household putting on a few pounds these days. The pregnant Playmate's husband, Rascal Flatts guitarist Joe Don Rooney, admits that he's eating a lot more, too.

I'm just preparing like any first time father could prepare ... just sweating bullets and eating lots of food," Rooney tells Dial-Global. "I'm eatin' for three now. So I'm gonna write a book called 'Eating For Three' from the husband's perspective."

The couple's baby boy is due at the beginning of June. Rooney says he's over the moon about being a first-time dad.

"It's amazing. It's unbelievable," he gushed. "I can't wait to be a father."