Spanx Is Embroiled In An Ugly Legal Battle With A 'Real Housewife'

Skip Bolen/Getty ImagesFormer "Real Housewife" and Yummie Tummy shapewear creator Heather Thomson is accusing Spanx of copying the design of some of her control tank tops.

Thomson says that she plans to take legal action against Spanx founder Sara Blakely.

It all began when Thomson allegedly "received a package at her Seventh Avenue offices that contained an anonymous note and a control tank top bearing a Spanx label which the note claimed was being sold on QVC," reports Karyn Monget at Women's Wear Daily.

Thomson said she immediately recognized the tank as one she sold with the Yummie Tummy brand and wrote a letter to Spanx alleging that it was an infringement on a patent.

Spanx filed for a declaratory judgment in court saying that it didn't violate any patents, but Thomson said she intends to fight back.

Spanx gave WWD this comment.

“Spanx was making shaping camisoles long before Yummie Tummie. We have no further comment. The papers filed in court provide our position at this time.”

Thomson, who was a Real Housewife of New York, successfully sued Maidenform Brands for $6.75 million in 2011 for copying her designs.

But Spanx would be a more formidable partner since the company essentially started the shapewear trend in 2000.

Patent lawsuits are traditionally difficult to win, so Thomson faces an uphill battle.