The Super Seeds trio are clad in branded suits, brightly coloured capes and masks, and can be spotted beside large tubs, which contain 9Bar's Super Seeds Breakfast Boost Bar variety.
Commuters are being invited to pay a visit to the trio to pick up free samples of the product.
The activity was unveiled at Waterloo station on Tuesday (12 January) and the team can be spotted at Euston today (14 January), where the first nine people to whisper ‘Super Seeds I love you’ will receive an entire case of 9Bar product.
The superheroes are set to visit a number of other locations over a six-week period.
Agency PrettyGreen is working with 9Bar to deliver the activity.
Visit Florida similarly launched its month-long tuc-tuc campaign within Waterloo station, meanwhile in other health food news, SodaStream created a series of sugar statues to combat sugary drinks last December.