Organisers of Australia's Splendour In The Grass festival are scrambling to find a replacement for British band London Grammar after they became the third act to drop out of the music event within a week.

The trio cancelled the appearance on Monday night (21Jul14) due to an unspecified illness, just days before the festival kicks off on Friday (25Jul14).

The musicians announced the news in a post on their page, writing, "It's with great sadness that we must announce the cancellation of our trip to Australia & Splendour in the Grass this week due to illness. This is an incredibly sad situation for us as our last visit was one of the most memorable of our careers, but we do not feel that we can currently deliver the level of performance that you all deserve from us. Our fans in Australia have been hugely supportive of our music since the very beginning, and it pains us to have to disappoint any of you..."

London Grammar also pulled out of Scotland's T in the Park Festival earlier this month (Jul14) to allow singer Hannah Reid to recover from throat problems.

They are the third act to cancel an appearance at the Australian music event within a week. Saturday's (26Jul14) headliners Two Door Cinema Club axed their set after lead singer Alex Trimble was hospitalised with stomach problems last week (ends20Jul14).

U.S. rock band The Wild Feathers also scrapped their set due to scheduling conflicts.

Folk act City and Colour will be promoted to the headline spot on Saturday, while British band Foals and Australian rockers Mt Warning have also been drafted into the line-up. London Grammar's replacement is yet to be announced.

The Byron Bay Festival will take place this weekend (25-27Jul14) and feature acts including Lily Allen and Outkast.