Kate Sullivan and newborn Jack

Weekend news anchors Mai Martinez and Marissa Bailey are expected to alternate filling in alongside Rob Johnson on WBBM-Channel 2 newscasts for the next three months while Kate Sullivan is on maternity leave.

Sullivan, who co-anchors at 5, 6 and 10 p.m. weekdays on the CBS-owned station, last Thursday delivered a boy, John Michael Tillman. It’s a first child for Sullivan and Michael Tillman, who were married in December 2013.

“Thank YOU to everyone for all your prayers, kind words, and LOVE over the past few days,” Sullivan wrote on Facebook Friday. “My husband and I welcomed a new baby boy into the world last night . . . John Michael Tillman! We are calling him Jack . . . and feel so happy and grateful on this Friday for all the blessings that led to this TGIF moment. Hope you have a wonderful weekend and thanks again for all your kindness!”

Sullivan, 38, a native of Lakeville, Massachusetts, and graduate of the University of Notre Dame, joined CBS 2 in 2010 from WCBS-TV in New York.