Martha Stewart Changes Story on Homeless Woman Costume, Blames Craig Melvin

Martha Stewart's singing a whole new tune about her controversial homeless woman Halloween costume -- the billionaire is now, essentially, saying "TODAY" show host Craig Melvin made her do it ... by accident!

Here's the deal ... Martha was onstage Tuesday at the CrossCountry Mortgage Sales Rally in Orlando when she decided to bring up her outrageous Halloween costume, but this time she revealed it all started with Craig ... who'd dressed as Snoop Dogg Friday on "TODAY."

Martha recounted Craig accidentally spilling chocolate all over her sweater, which she was going to wear to a costume party later that night.

Thing is, Martha says she only had 10 minutes to put her costume together, so the easiest idea she came up with was to dress as a "bum" ... her word, not ours.  

She told the crowd her costume was not meant as an insult, but she issued a public apology anyway because of the backlash.

Here's the thing ... Martha's latest story flies in the face of what she told TMZ a few days ago ... when she claimed she was bringing awareness to the issue of homelessness.

She initially told us, "I am distressed that my Halloween costume yesterday, which was intended to bring more awareness to the very serious subject of homelessness, has offended people, which was never my intention."

So, what's the real deal ... charitable outreach, or making the most of a "bum" situation?