The singer replied to a message from the fan in which she suggested that therapy could “wait”, while Styles’s second solo album, which some believe will be released soon, couldn’t.
“I guess therapy can wait... HS2 [as the album has been dubbed] and tour can’t,” the fan wrote.
Styles, however, spotted the message and encouraged the fan to take a different course of action.
“Go to therapy, it’s important. I’ll wait for you,” he wrote, adding the hashtag #WorldMentalHealth.
World Mental Health Day, which is on 10 October, aims to raise awareness of mental health issues and contribute to erasing stigma.
Some fans became convinced Styles was teasing an imminent new album on Thursday after spotting posters with the sentence: “Do you know who you are?”
The posters don’t mention the singer’s name but they bear the letters TPWK, which Styles has used on his merchandise as an acronym for “Treat People With Kindness”.
Photos posted on social media also show that the posters appear to sport the logo of Columbia Records, the label with which Styles signed in 2016 and which has represented him as a solo artist.
Styles also tweeted the word “Do” on 5 October, suggesting a link to the sentence “Do you know who you are?”.