Last week, Pounds posted clips of the pair in the studio, filmed by Payne’s sister Ruth, who co-wrote the track.
He also posted artwork showing an angel below a broken black heart.
Talking about its planned official release, Pounds wrote on X: “I pray that this will be a blessing to the world like Liam has always dreamed.
“I pray angels will comfort you all every day while listening. I pray that this song will be a blessing to Ruth, Bear, and the entire family.”
Payne shared his seven-year-old son, Bear, with Girls Aloud star Cheryl, who he was in a relationship with from 2016 to 2018.
Following his death, all five One Direction albums have returned to the UK top 40.
After leaving the group, Payne had top 10 hits with Rita Ora and Quavo. His last solo song, Teardrops, which was released earlier this year, reached number 85.
The 31-year-old singer died when he fell from the third-floor balcony of a hotel in Buenos Aires on 16 October.
The Public Prosecutor’s Office in Argentina is continuing to investigate the circumstances around his death.