Mafia II developer 2K Czech is contributing to Grand Theft Auto 5, VG247 has been told.
A source told us the Czech studio has been working on the game for almost a year, putting its cinematic expertise to work in producing animations for cutscenes and general gameplay.
The Rockstar-led project was announced in November 2011, but platform and release information is yet to surface.
The tech sharing goes both way, with Rockstar opening its secrets to 2K Czech. Our source tells us the collaboration is part of Take Two's plan to turn the Mafia series into a major franchise.
2K Czech's next game, Mafia 3, has apparently just gone into full development after a year of thorough pre-production, in which the game's concepts and tech were stripped back to basics and rebuilt.
Our source has no details on Mafia 3's intended release window or platforms, but noted that 2K was in attendance at the "Durango" developer's summit in London, rumoured to be an insider reveal of the next Xbox console.
Mafia 2 released in August 2010 and received extremely divisive reviews, with critics praising its story, characters and richly-detailed world but criticising the gameplay.
When approached for a statement, 2K advised it does not comment on rumours.