Owain Wyn Evans made the announcement on his own radio show when he said Ball would be joined by Rylan to make the announcement.
He teased fans about the highly anticipated entry by saying: "Who's it going to be? You'll have to wait and find out."
A specific time wasn't given for the announcement but Ball's show airs between 6:30am and 9:30am.
Rylan, who will be announcing the act with her, hit out at ticket touts yesterday after tickets for Eurovision went on sale.
With tickets for the final sold out in just over 30 minutes, they could be found on secondary ticketing prices at highly inflated prices. Some tickets for the final were being sold for £3500.
Rylan criticised touts for taking tickets from real fans on his Twitter, writing: "To the people selling Eurovision tickets at RIDICULOUS resale prices that arnt proper fans - p*****," along with a gif of a man giving the middle finger.
Ticketmaster's website was also beset with problems as fans tried to purchase tickets for the event. Tickets went on sale at midday yesterday but Ticketmaster suffered technical problems just minutes before with many fans encountering an error message or being kicked out of the virtual queue.
Osman joked: "Didn't get Eurovision tickets. My only hope now is to sing the U.K. entry."
While Quek commented: "If it makes anyone feel better… I couldn’t get #Eurovision Grand Final tickets…and I’m presenting the Opening Ceremony!"
The Eurovision grand final is set for 13 May at Liverpool's M&S Bank Arena and will be broadcast on the BBC.
Watch below: Eurovision final tickets sell out in 36 minutes