The recurring theme is music for fathers and sons, said the event's website.
The head organizer Jüri Makarov added that they may sign more artists as some negotiations are still taking place.
The orginizers took heat after announcing the event at the beginning of February without revealing any headliners, while still asking 50 euros for tickets. The price of a ticket to the two-day festival will cost 60 euros from Friday and 90 euros in June.
The original three-day festival was subtitled “Glasnost Rock - Rock for Peace!" and was held during a time of increasing defiance against Soviet rule. The free event in 1988 attracted 190,000 people.
Rock Summer was then repeated nearly every year for the following decade, attracting names like Iggy Pop and Shaggy to what was otherwise a backwater of the international music circuit. The last time it was held was 1997, after which the organizers went bankrupt.
Rock Summer 25 will be held at the Tallinn Song Festival Grounds on June 15 and 16.
Source: Estonian Public Broadcasting