GUMBOOTS and umbrellas were the must-have fashion accessories as torrential rain hit the Gympie Muster site.

Campsites were saturated and there was mud as far as the eye could see, but it didn't stop festival revellers from having a good time.

And if that much rain didn't dampen spirits, the late withdrawal of star attraction Adam Harvey certainly wasn't going to.

Harvey was scheduled to perform last night but took to his Facebook fan page to announce he had been taken ill.

"I'm devastated. I'm that crook and I can hardly speak let alone sing. I feel bloody awful for letting the country crowd down," he wrote.

The Muster may have set new crowd records, with country music fans pouring into the site and filling the camping area by Friday night, forcing an overflow into the Amamoor Showground.

With the rain expected to ease today, the action will continue with the likes of John Williamson, Beccy Cole, Montgomery Gentry and Ash Grunwald set to delight their enthusiastic fans.