Drums at the Grand Ole Opry

I’ve heard over-and-over how drums weren’t allowed at the Grand Ole Opry for many, many years. I know that there were a few isolated (surreptitious) incidents of an actual drumkit on stage with artists such as Bob Wills and Hank Thompson, but I am wondering if anyone knows when an actual drumkit began a regular presence (drums on stage at all times) during Opry broadcasts?

I have nothing to back this up except for a dim memory of something I once read, but I believe Hank Williams was the first act to regularly have drums at the Opry.