O.S.T.R - Adam Ostrowski - Polish hip-hop hero, musician, record producer, instumentalist and rapper. He graduated from the Academy of Music in Łódź, violin class. He's one of the most industrious and talented artists in Poland. He has achieve almost everything on Polish hip-hop scene.

O.S.T.R. is currently the author of 20 music albums. He got 6 gold and 7 platinum (one double and one triple platinum) album awards. For over a dozen years he is now on tour non-stop. On 23rd of February 2018 he released his new album ‘W drodze po szczescie’ (eng. ‘On the way to happiness’). His previous album 'Życie po śmierci' (eng. 'Life after Death') has exceeded more than 100.000 copies, becoming the best selling CD in Poland in 2016.

O.S.T.R. is now one of the most famous and respected rapper in Poland.