Ron Artest -- AKA Mr. Metta World Peace -- just went on " TMZ Live " ... and said he kept his name-change plans so secretive ... his OWN WIFE HAD NO IDEA ... until TMZ broke the story.

Metta claims he's been toying with the idea of changing his name for a while ... and was thiiiiiiiis close to settling on Mr. One Love ... but ultimately went with Metta World Peace because it would have a bigger global impact.