Borussia Dortmund and Liverpool supporters will join forces to demonstrate against rising ticket prices in football when the two teams meet at the Westfalenstadion in the Europa League on Thursday.
Both sets of fans have played a leading role in the fight to keep prices in domestic leagues affordable.
The Kein Zwanni ('No to €20') movement, protesting against prices in the Bundesliga when ticket costs for away standing increased above €20, was initiated by Dortmund supporters in 2010.
Liverpool fan groups Spion Kop 1906 and Spirit of Shankly, meanwhile, will mastermind the Liverpool protests.
In February, fans at Anfield staged a walkout in the closing stages of the game against Sunderland to protest against proposed ticket price increases at their ground. The rises were later shelved by owners Fenway Sports Group.
Marc Quambusch, a BVB supporter and Kein Zwanni spokesperson, told kicker the protests would show that "we have achieved a lot, but there is still a long way to go."
Quambusch added: "It can't be that football turns into a sport for the rich."
He explained that "folks from Liverpool contacted us right after the draw and said that we could join forces. We thought that was a cool idea, and it was only about the question what exactly we'd do."
Earlier this season, Premier League clubs reached a three-season agreement to cap away ticket prices at £30.
"That was a good start, but nothing more. We now have to make sure that prices don't increase after three years," Declan Tanner of the Spion Kop 1906 fan group told kicker.
"Younger fans who are over 18 and have to pay full price often cannot afford a stadium visit."
At Tuesday's Champions League match against Benfica, Bayern Munich fans protested against plans to introduce a European Super League, an idea that has been backed by club CEO Karl-Heinz Rummenigge in recent months.