Even online gamblers are sinking their claws into the 'Tiger King' -- and bookies have a strong hunch about who should don the mullet and leg brace in a feature film.

The oddsmakers at SportsBetting.ag have a list of A-listers they want folks to place bets on to play Joe Exotic ... who's become a worldwide phenomenon with the Netflix documentary. Their first choice won't surprise you much, but the underdog might.

The odds-on favorite is ... Kevin Bacon! If you place $100 on him, you'd only get $150 if he landed the role. Next is Ed Norton, who'd earn you $250 on a $100 bet. After that, it's Billy Bob Thornton and David Spade, who'd pay out $300 and $400, respectively, if they were cast.

As for your long shot ... that's Mr. Ben Stiller.

Btw, there’s a catch ... the film’s gotta be released by 2021 or sooner.

Of course, the gambling world offers equal opportunity ... to lose your money ... so folks are also weighing in on who plays Joe's archnemesis, Carole Baskin.

The favorite is Wendi McLendon-Covey (Deputy Johnson from 'Reno 911!') at an even split of +100 -- so you'd break even on a $100 bet. Down the line in order from most to least likely to land the part -- Allison Janney at +300, Kristen Wiig at +300, Jennifer Coolidge at +500 and finally, Laura Dern at +600.

There's other interesting 'Tiger King' categories over at MyBookie -- stuff like whether Joe will get a presidential pardon and will Carole be found guilty of murdering her husband.