Newport rappers Goldie Lookin' Chain are the latest act confirmed for the sell-out tsunami benefit concert at the Millennium Stadium in Cardiff.
The group said: "It's all about the people who've gone out and bought these 60,000 tickets in record time, we're just doing what we can to help."
Saturday's gig features a line-up including Eric Clapton, Keane and Manic Street Preachers.
Radio 1 DJ Edith Bowman has also been unveiled as one of the show's hosts.
The concert will also be broadcast by the BBC on TV, radio and online.
"Goldie Lookin' Chain brings the total to 18 acts performing on the day, almost as many acts as there are members of the Chain I think," said Paul Sergeant Millennium Stadium general manager.
"It means we have an incredibly diverse line-up - something for everyone."
Eric Clapton was one of the first to agree to play
Mr Sergeant said Edith Bowman sent a text message to one of the show co-ordinators offering her help after she heard the announcement of the concert.
"We were very touched by Edith's personal text message and immediately put her to the top of the presenters' pile," he said.
An extra batch of 1,000 tickets were sold within 20 minutes on Tuesday.
Veteran Scottish singer Lulu, who shot to fame on the back of her hit single Shout in the 1960s, was also added to the roster of acts on Tuesday.
Others include Jools Holland, Embrace, Badly Drawn Boy, Aled Jones, Charlotte Church, and Stereophonics' frontman Kelly Jones.
Meanwhile, Cardiff council has warned show-goers to plan their journeys.
Councillor Jim James, executive member for traffic and transportation, said: "Cardiff City are playing at home so Leckwith Stadium won't be open for park and ride, so the city will be full of concert-goers, football fans and shoppers.
"Therefore my advice would be to plan your journey carefully, leave yourself plenty of time to get to the concert and use public transport if possible."
Concert-goers arriving east of Cardiff will be advised to leave the M4 at junction 29 and those who arrive from the west, junction 33.
There will be park and ride facilities at the University Hospital of Wales, County Hall and Companies House.
A full city centre road closure will operate in Cardiff from 1300 to 2330 GMT on Saturday.
Travellers can call Connect 2 Cardiff on 029 2087 2087 or log onto www.traffic-wales.com.