The pop superstar will release new single Easy on Me next week.
She shared a short video on Twitter containing the opening bars of the piano-led track and confirmed it will arrive on Friday, October 15.
In the black and white clip, the 33-year-old is seen inserting a cassette into a car stereo and driving down a country lane while pieces of paper fly out of the windows of her car.
The snippet points towards the emotive kind of piano ballad the south London singer is best known for, but stops before any vocals are heard.
It comes after Adele sparked speculation that new music was on the way by updating her social media accounts and website on Monday.
Her Twitter and Instagram pages showed a blue and turquoise pattern with her biography containing a link to her website, which urged fans to sign up for more information.
After fans spotted the change in Adele’s online presence, the hashtag #Adele30 began trending.
It comes after the number 30 appeared on billboards and was projected on to famous landmarks around the world – including in Dubai, Ireland, France, Italy and the US.
The singer hinted her fourth album would be titled 30 in a 2019 post on Instagram, jokingly telling fans: ‘30 will be a drum and bass record to spite you all.’
Adele has not released an album since 2015’s 25, but she has confirmed she is working on a new record.
All three of her studio albums so far have been named after the milestone ages she hit during the creative process.
Adele, who headlined Glastonbury festival in 2016, announced her split from charity boss Simon Konecki in April 2019.
Their divorce was finalised in March this year, and they share custody of eight-year-old son Angelo.
She has also made headlines for her weight loss, sharing pictures on social media of her slimmer figure while living in the US.
Adele is reportedly dating American sports agent Rich Paul, founder of management company Klutch Sports Group, which represents high-profile basketball stars including LeBron James, Anthony Davis and John Wall.