A video revealing the as-yet unnamed device shows one of the existing Joy-Con controllers inserted into the ring, while the other is strapped to the player’s leg.
People are then seen pulling and squeezing the peripheral in various states, which appears to have some resistance, suggesting that it may serve as a product for fitness-related games.
Getting in on fitness is not new territory for the Japanese firm, having previously introduced a Wii Fit balance board to its Wii games console.
The company is planning to reveal more details about the “new experience” on September 12.
In July, Nintendo said that it had sold more than 36.87 million Switch consoles since sales began about two years ago.
The machine was launched in March 2017 to critical acclaim, as the first of its kind that enabled users to play games on its remote screen and then be docked and connected to a TV to continue playing in a home console set-up.
Its success has been credited as being a key part of helping Japanese gaming giant Nintendo return to profitability in recent years.
Nintendo Labo, an innovative cardboard-creating product for the Nintendo Switch, won a Bafta Games award in April.