When Juan Mata launched his Common Goal initiative, he said he hoped to "change the world, even if only in some small way".
The Manchester United midfielder pledged to donate 1% of his salary to charity, and called for others in football to do the same.
"I am leading this effort, but I don't want to be alone," said the Spaniard.
Two years on, more than 130 people have joined the cause.
Last month, two of those - Liverpool manager Jurgen Klopp and World Cup winner Megan Rapinoe - gave impassioned speeches at the Fifa Best Awards about the importance of football showing more social responsibility.
Klopp, the world's best coach, said "now is the time for those interested to step forward". USA winger Rapinoe, women's player of the year, went further. She told an audience that included Lionel Messi, Cristiano Ronaldo and Virgil van Dijk to "lend your platform to lift people up, to use this beautiful game to change the world for the better".
Speaking to BBC Sport this week, Mata approved.
"We can use the platform that we have to really be honest with ourselves, to really share our values or to really say what we think, or what football should be aiming for, and Megan is obviously an example of speaking from the heart," he said.
"I think the power of sport and of football in particular is huge and we should all realise that."
The 31-year-old said Klopp's decision to join Common Goal made all of the members "proud".
"It shows many people in football think the same way we do and realise the power of football," he said. "I am grateful for the way he did it, when he was receiving an award in front of everyone in the football world."
Yet while Klopp - manager of United's great rivals, and preparing for a Premier League trip to Old Trafford on Sunday - has signed up for Common Goal, no other male United player has done so.
Evidently it was disappointing when Mata failed to get the XI he wanted to launch Common Goal in August 2017.
"We didn't manage to do get 11 so I said: 'OK, I am going to be the first player to say it publicly, then hopefully, when others get to see what Common Goal is and find out what we are doing, they will join'," he said.
Mata would obviously be happy if United team-mates joined him, but added: "This is not about saying that whoever is in Common Goal is great and whoever isn't could do more.
"I really believe this is something that, whether it takes more or less time, will become gradually bigger and bigger."
It is nothing new for football figures to speak out about social issues. But it feels a door is being opened - with Rapinoe expressing her wish, among other things, that "everybody other than [Raheem] Sterling and [Kalidou] Koulibaly was as outraged about racism as they were".
Mata, who is donating proceeds from the sale of his recently-released autobiography 'Suddenly a Footballer' to Common Goal, endorses that sentiment.
"We can use the platform we have to be honest with ourselves, share our values or say what we think," he said.
"In the past, sport was something you enjoy and that's it, nothing to do with society or the social problems that we can have. But the power of sport is huge. We should all realise that."
Giorgio Chiellini and Mats Hummels are among the other high-profile figures to have signed up to Common Goal.
Four current Premier League players - Kasper Schmeichel, Charlie Daniels, Leon Balogun and Isaac Christie-Davies - have joined. Mata sees that as good news.
But, given there are about 500 players in the 20 Premier League first-team squads, that represents 1.25% of the total. The Professional Footballers' Association has 4,000 members.
So what might be stopping more players from joining?
Lack of awareness is the view of a Common Goal insider.
A large number of football players, so the theory goes, are, by nature, isolated from the real world and its problems. This is not necessarily because they don't care but it is maybe not on their personal radar.
This means many players rely on agents or advisers to guide them.
"You can't generalise because some of the modern-thinking ones have helped," said the Common Goal source. "But many still think putting a player's name and image next to a charity is enough.
"This has changed. Consumers see this kind of 'photo-op support' as an empty gesture. Nowadays people expect to see genuine commitment to causes."
The argument is extended across the game.
"Why can't investment in social impact become a systematic part of the various revenue streams within football?" said the source. "Imagine if 1% of the transfer market was invested in grassroots football organisations. How much better would we feel about the transfer market?
"If you took 1% of what was generated by football last year, that would be more than £400m. Nobody in the industry would even notice. This figure would allow football to be a major player in shaping the future of the planet."
Those types of funds are way beyond Common Goal at present.
But the charity is working on multiple projects: to promote peace in Colombia, raise HIV and Aids awareness in Nigeria, to tackle youth unemployment in the UK. Bayern Munich forward Serge Gnabry spent time in Ivory Coast last summer to meet one of the organisations he works with.
Mata feels the interaction is invaluable.
"If you want to just pay money and forget about it, you can - but I don't think that is ideal," he said.
"What is ideal is to really get behind the whole idea. If you can go and visit first hand where your donation is going to, to see the impact it is having and the people those funds are helping.
"Our ultimate goal and dream is that one day, this won't just be my one percent but one percent of professional football will go to social causes."