Get better soon, Niall! On Monday (May 4), Niall Horan opened up about his recent silence on social media, explaining he’s come down with an unspecified illness.

“Sorry been quiet guys, haven’t been feeling very well last few days. . I’ll be back soon x,” the former One Direction-er tweeted.

While Horan has been under the weather, his former 1D bandmates — Louis Tomlinson, Liam Payne and Harry Styles — have been vocal about reuniting for the 10-year anniversary of the boy band’s formation of the U.K. version of The X Factor. (While fifth member Zayn — whose longtime love Gigi Hadid confirmed last week she’s expecting a child with the singer — has remained mum on the potential reunion, his former bandmates have all followed him on social platforms for the first time since he abruptly quit the group in 2015.)

The singer also teamed up with fellow U.K. stars Olly Murs, James Arthur and McFly‘s Tom Fletcher and Danny Jones over the weekend for a socially-distanced cover of the English pop-rock band’s 2010 single “Shine A Light” dedicated to healthcare workers on the front line of the coronavirus pandemic.

Billboard has reached out to Horan’s rep for additional comment.

See Horan’s tweet below.