Tattle-tale or tattle-tell?

"Tattle" is a verb, meaning to reveal the plans or ideas of another, or to gossip, so you could say, "I'm gonna tattle on you", which means about the same as "I'm gonna tell on you". So a tattle-tale is someone who tells tales. It's the only way I've ever heard it. Never heard "tattle-tell", which is an unlikely construction since it's two verbs in a rown.

www.dictionary.com has it spelled as either tattle-tale or tattletale, but no entries at all for tattle-tell.

Thank you username!

Tattle tale tit
Your tongue shall be slit,
And every dog in our town
Shall have a little bit.

Also "telling tales out of school"--modernized as "What happens in Vegas..."

There's a telltale bump showing on that blanket..