Zion Williamson didn't get much time to celebrate being a girl dad before becoming the center of some bombshell allegations ... 'cause a popular porn star says the hooper "better pray" he's not about to be a father of two.
32-year-old Moriah Mills -- a music artist and OnlyFans model with more than a million followers on Twitter -- alleged she is in a romantic relationship with the New Orleans Pelicans forward in a Twitter rant on Wednesday ... claiming she had no idea he was seeing someone else, let alone expecting a baby, too.
Mills says she was intimate with Zion as recently as last week ... and posted alleged Snapchat messages that appear to show him arranging to have her move to New Orleans.
Moriah gave X-rated details about her alleged experiences with Zion -- she also took credit for getting him get back into shape as he sat out the majority of the season with an injury.
"Better pray I’m not pregnant too because I’m definitely late @Zionwilliamson," Moriah added.
Zion's GF, Ahkeema, appeared to respond to Moriah's tirade ... saying, "Happy hoes ain't hating and hating hoes ain't happy."
Moriah clapped back ... saying, "You not on my level mah believe that."
Zion and Ahkeema shared footage of their gender reveal party on Tuesday ... which showed they are expecting a baby girl together.
Zion has yet to address Moriah's allegations.