"Idina Menzel and Taye Diggs have jointly decided to separate at this time," the publicist said. "Their primary focus and concern is for their son. We ask that you respect their privacy during this time."
No specific reason was given for the breakup.
Diggs and Menzel, both 42, met when they co-starred in the original production of the Broadway musical "Rent" in the mid-1990s.
They were married in 2003 and appeared together in the movie musical version of "Rent" in 2005. Their son, Walker, was born in 2009.
Menzel plays Elsa in the animated movie musical "Frozen" and Diggs was a cast member on the recently wrapped "Private Practice."