Origin of "Dooon't You Belieeeeve It!"

[seosamh]

OK - another cartoon catchphrase-based post.

It featured on a few Tom & Jerry cartoons, usually after something (e.g. that radioactive white mouse) had blown up the entire earth or something. Tom would say, in a booming, doom-laden voice: “Dooooon’t you belieeeeeve it”.

A poster on this forum suggests that it may have been something to do with a Ripley’s Believe It Or Not film from the 1930’s. Can anyone here corroborate or refute that?

[Q.E.D]

While not even close to definitive, this message board thread seems to offer a reasonable explanation:

The only lead I’ve come across so far (and I think it’s probably a false one) is that in 1943 John Nesbitt made a short (in his series Passing Parade) called “DON’T YOU BELIEVE IT!” about various urban myths - if he delivered the words in that sonorous fashion this could be a contender, the timing is right - but I’ve heard extracts from his radio show along the same lines and his delivery wasn’t that melodramatic.

A bit later than your 1930s source, but plausible nevetheless.

[Larry_Mudd]

I’ve got a few episodes of *Don’t You Believe It[/] around somewhere.

It is definitely the source, the way it’s read is unmistakabe. “Dooon’t Youu Beelieve It!”.

[Q.E.D]

So, how does it compare to Mythbusters?