Kevin Costner's used to dancing with wolves, but on Friday night he was chatting with a stone-cold fox ... leaning in for a convo with Brooks Nader.

The actor and the model both attended a VIP dinner hosted by Scott Sartiano -- the owner of the popular NYC social club Zero Bond -- at his restaurant Sartiano's in the Wynn Hotel and Casino in Las Vegas to celebrate the opening of Zero Bond Las Vegas.

Eyewitnesses tell TMZ ... Costner and Nader were spotted chatting it up at dinner and hanging out in the high roller room of Zero Bond, where attendees played their choice of roulette, blackjack or poker.

Check out the pics ... there's no PDA between the two -- but it seems to be a friendly conversation. Unclear how well these two know each other, if at all.

They were far from the only famous faces who attended the dinner ... Gwyneth Paltrow, Orlando Bloom, Ryan Phillippe, Corey Gamble, Crayton Carrozza, Rachel Zoe, Jon Hamm, Jeffrey Beacher, Ashley Benson and many more stars also attended.

Looks like the beginning of a beautiful friendship between the two stars!