While it is not yet known who Malone is dating as she has chosen to spend very little time in the spotlight, TMZ reports the couple have been "happy privately building their relationship" and are excited to welcome a child together.
There has been no announcement on when the baby is due.
Many media outlets have taken to Twitter to congratulate the singer, iHeart Radio said "Post Malone is going to be a dad!!! Congratulations!"
E! News said "Now we wanna say CONGRATULATIONS! Post Malone is going to be a DAD."
In addition to the rapper's exciting news, he announced with a Tweet that he is releasing his latest album Twelve Carat Toothache next month on June 3.
The rapper said the album speaks "more to how I'm feeling at the moment: the ups and downs and the disarray and the bipolar aspect of being an artist in the mainstream".
It is set to feature some big names in the music industry like Doja Cat, The Weeknd and The Kid LAROI.