Apple managed to make it to one day before the release of its new iPad without letting the cat out of the bag.

Then Terry McGraw, owner of publishing company McGraw-Hill, had to open his yap.

Appearing on CNBC on Tuesday to talk business, McGraw started out safe, yammering about quarterly earnings and the economic downturn. And China. And cars. And all sorts of other nonsense. Lulling himself into a false sense of security, as it were.

Then around 2:50 of the attached video, host Erin Burnett pounces.

“And very quickly, Apple,” Burnett says. “Apparently, you may get textbooks on this new tablet (the iPad) that’s coming out.”

“Yes, very exciting,” McGraw says. “They’ll make their announcement on this one tomorrow (Wednesday). We have worked for Apple for quite a while and the tablet is going to be based on the iPhone operating system.”

Whoops.

No telling what notoriously tight-lipped, secrecy obsessed Apple boss Steve Jobs said when he saw that one.