January Jones Welcomes Baby Boy

Actress January Jones attends the premiere of "X-Men: First Class" at The Ziegfeld Theater on Wednesday, May 25, 2011 in New York. (AP)

January Jones welcomed a son Tuesday, a rep for the "Mad Men" star confirms to PEOPLE.

Son, Xander Dane Jones is the actress' first child, and a source tells PEOPLE, "She's really looking forward to this new chapter in her life as a single mom."

Jones, 33, had kept the baby's sex a secret after announcing her pregnancy in April.