Dixie Chick Martie Maguire Is Expecting

Originally posted Sunday January 27, 2008 08:30 PM EST

Dixie Chick Martie Maguire is pregnant, she told PEOPLE on the red carpet for the Nobelity Artists & Filmmakers Dinner in Austin to benefit the Nobelity Project Sunday.

"I'm very excited," Maguire, 38, says, adding, "We know what it is – it's a girl."

Maguire, 38, is married to Gareth Maguire, a professor. Their first children together were twin daughters Eva Ruth and Kathleen Emilie, who were born in April 2004. "I'm feeling good now, although I wasn't!" Maguire jokes. "Carrying one instead of two will be much easier."

In regard to the growing brood between her and the rest of the Dixies – Natalie Maines and Emily Robison – Maguire says, "We'll have to move over and let the little chicks take over! We've got a new band!