The Man Utd midfielder co-founded the charity which aims to tackle social issues using donations from the football community.
Members are urged to donate 1 per cent of their salary to a central fund, from which it is re-dispersed to high-impact non-profit organisations.
“I want to take the opportunity with this post to publicly thank Jürgen Klopp for joining Common Goal and the way in which he did it, in front of the whole footballing world,” Mata said.
“Obviously we are big rivals out on the pitch, but this movement doesn’t look at rivalries as off the pitch we are united by the same objective.”
Klopp has joined the likes of US women’s star Megan Rapinoe, and Leicester goalkeeper Kasper Schmeichel in signing up to the initiative, and announced his involvement when collecting his award for FIFA Best Coach of the Year on Monday.
“The past was great, the present is really good and the future hopefully will be good for us as well,” Klopp said. “But there are people out there that are not exactly in the same situation.
“I am really proud and happy to announce that from today on I am member of the Common Goal family.
“Liverpool’s Champions League win was achieved on the back of exceptional team spirit among the staff and players and it is only by working together that we can accomplish truly meaningful things in football and in life.
“As a team, even with a minimum pledge of just 1%, together the football industry is capable of transforming the world. Now is the time for those interested to take a step forward.”
Common Goal’s aim is to use donated funds to help disadvantaged young people and their communities.
Their work has already seen them undertake a peacebuilding project in Colombia, raise awareness of HIV and Aids in Nigeria, and tackle youth unemployment in the UK, among others.
They now boast over 380 members and support from 135 organisations.