RIHANNA is officially pregnant . . . it’s not just a rumor this time.  She and her boyfriend A$AP ROCKY are expecting their first child together.

She debuted her baby bump with A$AP during a snowy walk in Harlem over the weekend.  She wore a long bright pink jacket with low-rise jeans . . . her baby bump was exposed with a jeweled gold cross and pearl chain that hung over.

Rihanna’s dad commented on the news.  “I’m ecstatic . . . I’m so happy that I jumped for joy.  I’m still so excited.  [She’s] always said that she wanted children, she loves kids . . . she’s going to be a good mom.”