Gladys Knight has credited her Christian faith with helping her succeed at marriage.

The 78-year-old 'Midnight Train to Georgia' star has been married to her husband William McDowell for 21 years after three previous failed marriages and she's revealed they turn to God every time they hit a rocky patch and it keeps their relationship strong and healthy.

She told America's Closer magazine: "You have to always know that the Lord is going to make a way. We put him first. If you've got a problem and don't know how to do something, you have to look up. That's how we get through."

Gladys has three children from previous relationships and she credits her mother Sarah with giving her the help and support she needed so she could balance life as a musician with raising her kids.

She added to the publication: "You know, I love my babies. They were ... beautiful but without my mother, I don't think I would have been able to do it. I had an amazing mother who said: 'You go do this and I'm gonna do this'. You don't have a whole lot of parents in that situation who would be willing to take over and help you like that, so that you could [make a better life] for your children. But that's the way she worked."

Gladys and William now have 17 grandchildren and 10 great-grandchildren between them and the singer insists her husband is devoted to them.

She added: "When I'm at home, I have a houseful of kids. And they're all over William, my husband. He is all about the kids and they just love him to death. They love him the best! And he will do anything to keep them on the right track."