Haim's new single Summer Girl was inspired by the cancer diagnosis of singer Danielle Haim's partner.

The group premiered the track at a recent Los Angeles show, and on the eve of its release, Danielle took to social media to open up about the sad story behind it.

"summer girl is out tomo (tomorrow)...," she wrote on Tuesday (30Jul19). "I wrote it around the time my partner was diagnosed with cancer a couple years ago... (he’s in the clear now!) we were touring on and off at this time and every time we were on the phone with each other or when I would come home in between shows, I wanted to be this light that shined on him when he was feeling very dark.

"I wanted to be his hope when he was feeling hopeless. so I kept singing these lines - I’m your sunny girl/I’m your fuzzy girl/I’m your summer girl - over the bass line. summer girl stuck.

"fast forward to a couple months ago - I remembered this demo and pulled it up from my phone."

Haim explained a pal came up with a saxophone solo and "it all clicked".

"we were kinda joking about how the doot doot doot part reminded us of (Lou Reed song) walk on the wild side... (it's) v (very) inspired by Lou (Reed) and we kept it that way. I brought it back to my partner Ariel - where the inspo (inspiration) first started - and he put some finishing touches on it and here we are!"