The choir, who came third in Britain's Got Talent earlier this year, will be joining Nu Sxool and Joe McElderry on stage at St Helen's on Monday November 5. Geordie Joe rose to fame by winning smash hit TV programme The X Factor in 2009.
Only Boys Aloud, a South Wales-based choir made up of boys aged 14 to 19, have become well-known for rousing renditions of Welsh hymns like Calon Lan.
Swansea Council is behind the event. The gates will open at 5.30pm with entertainment starting at 6pm and fireworks starting at 7.30pm.
Cllr Nick Bradley, Swansea Council's Cabinet Member for Regeneration, said: "It's fantastic news that another top act has been added to the line-up for the annual Bonfire Night festivities in St Helen's.
"The combination of Only Boys Aloud and Joe McElderry will appeal to people of all ages. Their performances will offer a terrific build-up to a feast of fireworks that will help Swansea mark Bonfire Night.
"The fact both acts made their names on massively successful reality TV programmes means there'll be a high demand for tickets, so I'd urge anyone interested in going along to get in touch soon and make sure they don't miss out."
The fireworks display is supported by Admiral and Nation 80s.
Gates open at 5.30pm, entertainment takes place from 6pm and fireworks start at 7.30pm.
Ring 01792 637300, visit http://www.swanseabayfestival.co.uk or call into Active Swansea leisure centres or the Tourist Information Office on Plymouth Street to get hold of tickets.
Tickets are priced from £3 to £5.50 and can be bought in advance or on the day, subject to availability. Family tickets are also available, starting at £15.