The Glasgow-based festival has said fans will be able to log on to its website on Tuesday at 4pm for the announcement.
Music lovers will be presented with clues to who the acts will be for next year's Glasgow Green festival, due to take place from July 10-12.
Treasure hunters will be asked to solve clues on different locations and venues, with correct answers revealing the names to the acts who will headline next year.
• READ MORE: TRNSMT 2019: Queen Tut’s stage ‘a step in the right direction’To take part, fans will have to go to www.trnsmtfest.com at 4pm on Tuesday.
Participants will then be in with a chance to win free tickets to the event if they share the correct answer on social media.
The festival, due to take place for the fourth time next year, was seen as a replacement for T in the Park - which ended in 2016.
Event organisers have also announced plans to hold a special "Black Friday" sale on tickets, which will give those who have signed up to the TRNSMT database a discount on three-day tickets to the festival for one week, before another tier of tickets are released in early December.
Megastars such as Stormzy, Radiohead, Lewis Capaldi and the Killers have all performed at the Glasgow festival since it was first held in 2017.