05/20/2009 at 08:00 PM EDT
Hip-hop artist Nas has filed a response to Kelis's divorce filing, asking a court to deny her any spousal support, court documents filed in Los Angeles show.
Kelis, 29, the "Milkshake" singer who's pregnant with their first child due in July, filed for divorce
from Nas, 35, last month. Both sides are seeking joint custody of the unborn child.
Although the couple went public with their marriage with a ceremony in 2005, the pair was secretly married at a courthouse in 2003, a source confirms.