COSTNER ON THE BRINK!

Career & love life on the line as pals fear secret breakdown

CAUTIOUS Kevin Costner has been unusually open about his private life as he goes around playing Mr. Nice Guy in recent interviews — mainly in a bid to shore up interest in his teetering vanity project Horizon — according to sources who squeal that deep down he’s “in a world of pain,” with friends worrying a full-blown meltdown is just around the corner!

Sources snitch the 69-year-old A-lister has everything riding on his Western saga, which earned him an 11-minute standing ovation from peers at the Cannes Film Festival premiere in May, but left a lot of critics less than thrilled.

“For all his bravado, he’s terrified Horizon will bleed him dry and he’ll lose a huge chunk of savings,” dishes an insider.