Country singer Jo Dee Messina has asked fans to pray for her ailing mother as she undergoes another surgery procedure.

The star's mum, Mary, has been in and out of hospital since having life-saving heart surgery in April (13), and she was admitted to a medical centre again in early July (13) with pneumonia.

Mary was back in the operating room on Tuesday for an undisclosed procedure and Messina is hopeful she will pull through.

Taking to, she writes, "Moms (sic) in surgery now. Please send up a prayer that god is w (with) surgeon and give him the wisdom and hands he needs to do his best".