4:05 PM PT -- Harry Styles is also paying tribute to Liam Payne ... saying he's "truly devastated" by Liam's death.
Harry says Liam's "greatest joy was making other people happy" ... and he's remembering Liam for living "wide open, with his heart on his sleeve." Harry also says Liam "had an energy for life that was infectious" and he was "warm, supportive and incredibly loving."
HS adds his heart breaks for Liam's family ... including his son, Bear.
2:08 PM PT -- Zayn Malik has issued his own personal tribute to late One Direction member Liam Payne ... expressing his sadness in a heartbreaking Instagram upload.
Alongside a photo of himself and Liam seemingly napping during their 1D touring days, Zayn shared his regret for never thanking LP for helping him through "some of the most difficult times," including when he was homesick at 17.
As he continued, Zayn remembered Liam as being "head strong" and "opinionated," admitting they "butted heads" at times. Nonetheless, Zayn said he "secretly respected" Liam for his give "no f**ks" attitude.
Zayn signed off his note by expressing his love for Liam, who he praised as "the most qualified" musician.
Louis Tomlinson is sharing his grief following the death of former One Direction bandmate Liam Payne ... posting a poignant tribute to his social media.
In the wake of Liam's death in Argentina Wednesday, Louis posted to Instagram, where he shared he is "beyond devastated" by his peer's untimely passing.
He wrote ... "Yesterday I lost a brother. Liam was somebody I looked up to everyday, such a positive, funny, and kind soul."