Malian group Tinariwen and Sweden's Mando Diao are the latest acts confirmed for this year's Heineken Open'er Festival.
The event, which won Best Major Festival at the inaugural European Festival Awards earlier this month, is set to be headlined by Pearl Jam and Kasabian.
Tickets are on sale now at a promotional price, meaning the earlier you book, the cheaper the tickets are.
Three-day camping passes are priced at 71 EUR, while four-day tickets will set you back 86 EUR. One-day tickets are around 37 EUR.
Click here to buy Open'er Festival tickets.
Open'er Festival 2010 will take place in Gdynia, Airport Gdynia-Kosakowo, Poland from 1-4 July.