The Paramore frontwoman announced in December that she is set to release her own project, 'Petals for Armor', and now she has confirmed the release date for the lead single.
She tweeted alongside a clip of breathing noises: "my first offering: 'SIMMER', drops 1.22.20
"see you then. (sic)"
The 'Misery Business' hitmaker revealed the new solo music was on its way whilst thanking her fans for their birthday messages.
Hayley wrote at the time: "Thanks so much for all the birthday wishes. 30 was a very important year. 31 will be too.
"I'm putting out some music next year. With the help of some of my closest friends, I made something I'm going to call my own. It's a really special project and you'll get a taste of it in January. Happy New Year, friends."
Hayley's announcement about her solo project came after she admitted she "doesn't know" what the future holds for Paramore.
The 'Still Into You' group have been on hiatus since last year, and Hayley admitted she and her bandmates - Taylor York and Zak Pharro - are enjoying being friends "without music" at the moment.
She said': "I really don't know what's next for Paramore.
"The guys and I just had dinner the other night at my house, and I think we're just really enjoying being friends and adult human beings at home by ourselves, without music."
Hayley previously admitted she wanted to disband Paramore - whose last album was 2017's 'After Laughter' - three years ago.
The 'Pressure' singer said the public criticisms and accusations of being controlling she faced on the departures of guitarist Josh Farro, her ex-boyfriend, and his brother, drummer Zac - who has since rejoined - in 2010, followed by bassist Jeremy Davis leaving in 2015, after launching a lawsuit against her and Taylor, left her feeling drained and seeking a fresh start.
She admitted: "Two years ago I asked Taylor if we could start a new band. I was so sick of this c**p. I said we should just try something new, give it a new name."
Taylor added: "I've wanted to quit this band so many times. Going through all this conflict and drama over the years ... I was just like, 'Man, I feel like we can keep going, but this is not worth it if we don't want to be here.' "
And the pair admitted they are unsure as to why they have continued.
Hayley said: "Honestly, I don't know. We, for some reason, kept showing up and kept writing and, little by little, the songs got better and we got a little more inspired to do it."