Subway is being sued by two women from the US who claim their sandwiches didn't actually contain any tuna.
Karen Dhanowa and Nilima Amin have filed a $5 million (£3.5m) lawsuit against the fast food giant after they were left disappointed with their tuna melts.
The disgruntled pair, from Alameda County, California, put their sandwiches through independent testing which allegedly "repeatedly affirmed" there wasn't any tuna in them, according to their lawsuit.
"The filling in the products has no scintilla of tuna at all," the papers, filed in the Northern District of California last week, claim, reports the New York Post.
Subway has denied their allegations.
The complainants claim tuna in the melts are in fact "a mixture of various concoctions" that "imitate the appearance" of the protein-rich fish.
And say it has been done as a shrewd money-saving measure, with their six-inch subs - which they were "tricked into buying" - costing $4.25 each.
Their lawyer Shalini Dogra told The Washington Post : "We found that the ingredients were not tuna and not fish."
The lawsuit brings claims of fraud, intentional misrepresentation, negligent misrepresentation, and unjust enrichment against the company.
And the pair want their claim certified as a class action, meaning other unhappy customers who bought a tuna sandwich or wrap after January 21, 2017 could join them.
A Subway spokesperson has called the allegations "baseless" and "are being pursued without adequate investigation".
"There simply is no truth to the allegations in the complaint that was filed in California," a statement read.
It adds the company "delivers 100% cooked tuna" to its customers without exception and that the claims "threaten to damage" its franchisees who are small business owners.
In September, Ireland's Supreme Court ruled there was too much sugar in Subway sandwiches for it to be legally considered bread.
The distinction meant the company could pay less in tax.
