The Killers kicked off the Mencap Little Noise Sessions over the weekend with a surprise performance in London.
By Damian Jones
Newsbeat music reporter
The Killers frontman Brandon Flowers performed a Cyndi Lauper hit
The Las Vegas rockers, who played a one-off show at the Royal Albert Hall last week, turned up at the charity gig at the Union Chapel for a three song stripped-back set.
The 10 day event is curated by Radio 1 DJ Jo Whiley. It helps raise awareness and provides support to people with learning disabilities.
The sessions have been running since 2006 and have featured Amy Winehouse, U2, Noel Gallagher and Snow Patrol in the past.
Lead singer Brandon Flowers was backed by a violinist as he performed a piano-driven version of new single Human and Smile Like You Mean It.
He then told the crowd: "We have decided to do a cover and who better than Cyndi Lauper?"
They went on to play her most famous hit Girls Just Want To Have Fun.
Bassist Mark Stoermer told Newsbeat: "It was a change of pace tonight. We've played a lot of places here in London but never one like this place.
"It's cool to do these things as kind of a one off and we don't normally play things stripped down like we did tonight. It was a lot of fun."
The band's forthcoming album Day & Age is due out on 24 November and the bassist said he's excited about how fans will react to their new record.
"We are at a place where our fans won't be too surprised and we have shown them that we have a wide range in terms of what we do," he added.
"We're always trying new things like the saxophone and we always approach each new song with a different attitude. If we feel we need to try something on a song we go for it. We don't just do those things for the hell of it.
"This album again is all over the place but fans that have been with us for the last couple of albums will get it."
Newcomers Cage The Elephant played an upbeat set which culminated in singer Matt Shultz jumping on to one the chapel's benches and singing in the crowd.
White Lies frontman Harry McVeigh then stepped up for a powerful performance on a solitary organ which saw him singing tracks from the band's forthcoming debut To Lose My Life including single Unfinished Business.
Glasvegas singer James Allan performed an acoustic number
Glasvegas headlined the night with a stripped-down five song set which saw singer James Allan perform on acoustic guitar with his brother and guitarist Rab for opener Flowers And Football Tops.
James then jokingly introduced the rest of the band for their second track before they covered The Ronettes classic Be My Baby.
Introducing the track he said: "This is for Jo (Whiley). She has a good heart I can tell."
Speaking about the cause Rab also told Newsbeat: "Up until now we've not really done a lot of stuff for charity.
"It's really nice to do it particularly for Jo because she has always been great with us and supported us.
"When she asked us, it wasn't a question if we were going to do it or not. We were going to make time because we know it means a lot to her."
The band ended the show with an organ-heavy rendition of album track Ice Cream Van.
Andrea Westwick, 26, who lives in London but is originally from Glasgow said: "It was really good because it was different from their normal shows.
"The Killers were amazing too and it was a surprise because some people were expecting Oasis. I've seen them at festivals, but to see them in a little church like this was fantastic."
But Daniel O'Shea, 24, from Wembley was disappointed with Glasvegas' performance.
He said: "I'm a big Glasvegas fan, I've seen them four times now but to come and sing a couple of songs is an absolute disgrace.
"I'm honoured to give my money to charity but any real band will always come out and sing their songs, go offstage, come back on and do a couple more songs."