Envestors, the London-based investment firm bought by Braveheart earlier this year, said it had secured financing from private investors for start-up company PayasUgym.
The gym outfit aims to offer casual users access to a network of sites on a pay as you go basis with no membership ties.
It hopes to launch next month, allowing customers to "load" cash on to an online account that can be used at a wide range of fitness centres, from spas to leisure centre gyms.
Jamie Ward, co-founder of the company, said: "Consumers are increasingly demanding more choice and flexibility with their gym memberships.
"PayasUgym will address these existing market restrictions and provide affordability and convenience for casual gym users."
Customers will be able to buy pay as you go passes through PayasUgym's website or with smartphone applications.
But it is likely to face competition in providing more affordable gym access, with serial entrepreneur Sir Stelios Haji-Ioannou planning to launch a budget fitness club offering next year.
Stelios is gearing up to launch EasyGym in the first half of 2011 allowing users to sign up for monthly-only contracts costing as little as 15 a month.
While not targeting the pay as you go market, the EasyGroup initiative is aimed squarely at those looking for a more affordable way to get fit.
The pair of new businesses will be entering an already competitive gyms market.
In 2009, leisure industries veteran Peter Roberts launched a no-frills gyms business to appeal to "health-conscious shift workers and those on a tight budget".
One of the first of his Pure Gym operations opened in the Quartermile development in Edinburgh.
He now has nine gyms open in his chain - including one in Glasgow - and has a further three sites planned for next year, with an Aberdeen venue opening in the spring.
Roberts, who launched the hotel chains Langdale Group and Golden Tulip, described the venture as "the EasyJet of the gyms business" because his sites are open 24 hours a day, but they do not provide bars and other facilities that more expensive clubs offer.PayasUgym was thought up by work colleagues Ward and Neil Harmsworth, who came up with the idea when travelling back from a customer meeting discussing the difficulties in finding a gym you can visit on a one-off basis.
It is set to go live on 21 January in London and the south-east of England, branching out across the UK later in 2011.
PayasUgym already has more than 100 gyms on board in London and the surrounding commuter belt.
Envestors specialises in matching high net-worth private investors with fast-growing start-up companies.
Oliver Woolley, managing director of Envestors, said: "We are pleased to have achieved this result for a company with a great business model that serves a real need."
The latest investment continues to a busy month for Braveheart and rounds off a hat-trick of deals.
Its Envestors subsidiary raised 1.5 million in ten weeks for Chargemaster, which makes equipment for electric vehicles.
At the start of the month, Aim-listed Braveheart also led a 300,000 funding round for Tayside Flow Technologies, an NHS spin-out that makes tubes that are inserted into patients arteries to help blood circulate.
Braveheart's clients, Scottish Enterprise, Quayle Munro and other private investors took part in the funding round for the firm, which also lists Kwik Fit entrepreneur Sir Tom Farmer among its backers.