Vanessa Carlton welcomes a daughter

Vanessa Carlton attends the 62nd annual BMI Pop Awards at the Regent Beverly Wilshire Hotel on May 13, 2014, in Beverly Hills, California.

Frazer Harrison/Getty Images

Vanessa Carlton is a mom.

The singer and her husband, Deer Tick singer-guitarist John McCauley, welcomed a daughter on Tuesday.

"Sid the Kid, whoa!!!" McCauley captioned an Instagram photo showing holding the baby girl.

Carlton added in a tweet, "Thanks for all the sweet wishes on our daughter. She's the quiet observer. We are in for it."

The singer, 34, married McCauley in December 2013 and confirmed her pregnancy back in June.