On Sunday, she posted a photo of her son looking upset along with the caption, "my son when he found out his sibling is going to the Oscars and not him."
The singer also posted a video of the baby, whose name has not been revealed, sitting on someone's lap watching a video of Rihanna on a laptop.
The Fenty Beauty founder lovingly referred to her son, whom she shares with partner A$AP Rocky, as "my fat man" in the caption of her post. She previously unveiled her son's face on TikTok and in the pages of British Vogue.
Rihanna revealed she was pregnant with her second child with A$AP Rocky while performing during the Apple Music Super Bowl halftime show in February.
The Oscars air this coming Sunday on ABC starting at 8 p.m. ET.