KEVIN'S BIG PITY PARTY!

Costner moping as critics slam new flick & Jewel gets cold feet

YELLOWSTONE star Kevin Costner is turning into a brooding mope with the flop of his vanity project Horizon movie and fast-fading romance with songbird Jewel, according to sources who say worried pals are telling him to get it together and stop sulking.

"He's no fun anymore. The joy and the spring has gone out of his step," spills an insider.

The 69-year-old Oscar winner has been busy promoting the first part of his epic Civil War passion project and sources say the slamming critics gave it at the Cannes film fest still stings.