Defending champion Humphries will be aiming to become just the fourth man to successfully win back-to-back world titles when the tournament gets underway next month.

But Littler, who lost to Humphries after a historic run to the final, will be among the top seeds set to try and topple the 29-year-old.

The Grand Slam of Darts presents an opportunity for players to build up momentum heading into Alexandra Palace next month.

Humphries has been drawn in a group along with James Wade, Mickey Mansell and Rowby-John Rodriguez.

If he wins is group, he'll face the runner-up from Danny Noppert's group, which includes Martin Schindler, Cameron Menzies and Beau Graves.

Humphries is hopeful of a deep run to help his form, but an early exit won't derail his confidence for the World Championships.

"It's always nice and always helps you if you're winning big tournaments," Humphries said.

"There's a lot of people will put your name in the hat and think you're going to win again.

"Of course, if it doesn't go to plan I'll always be dangerous in the world championships.

"The longer format really does benefit me so it's a great opportunity for me to get some more silverware and give myself even more confidence than I've already got."

Group matches in the Grand Slam of Darts are best-of-nine legs but that increases to best-of-19 legs in the second round before going to best-of-31 legs.

But the shorter matches in the group stage could spring a few surprises and Humphries is well aware that he will be need to be on top of his game.

"I think every group is going to be tough," Humphries said.

"I've got a few lower-ranked players in there and then with James Wade as well but I've never taken anyone for granted in my whole life and I certainly won't start now.

"It's a best-of-nine game. Couple of bad legs and you're right under it.

"It wouldn't have mattered to me if it was the toughest or the worst draw.

"Anything can happen and I have to make sure I'm at my top level to make sure I don't slip up and not get out the group."