Question on someone announcing 'allin' out of turn

[Zorlac]

It's heads up on the river in an NL tournament. I've been betting on a draw (out of position) into a tight player trying to push them off their hand. On the river, I hit my straight and I'm considering how much to value bet when he announces out of turn "I'm allin". I have the nuts but before I can say "Call" someone at the table says "He's out of turn!"

What should happen here? Is his bet binding?

Otherwise, now I'm effectively screwed. If I check (hoping to check-raise) he's forced to check. If I bet, I'm effectively announcing I have the stone cold nuts to beat his all-in.


.Z