The comedian revealed the exciting news via Twitter on Wednesday.
It's an exciting day for Rosie O'Donnell!
The comedian is now a grandmother, after she revealed via Twitter on Wednesday that her 21-year-old daughter, Chelsea, gave birth to a beautiful baby girl, Skylar Rose.
Rosie shared a pic of Chelsea cradling the newborn with her boyfriend, Jacob Bourassa, by her side.
"My daughter chels - jake - and skylar rose my first grandchild !!!" Rosie captioned it, using the hashtags "#love," "#life," and "#NANA."
She also shared an additional close-up shot of the little bundle of "joy."
"Nana & Skylar," another post read. "#bigLOVE."
Rosie -- who adopted Chelsea when she was a baby with her then-wife Kelli Carpenter-O’Donnell -- has certainly had her fair share of ups and downs with her daughter over the past few years. However, a rep told ET in June that the two had reconnected after Chelsea learned she was pregnant.
"Rosie said, yes, she’s pregnant and they reconnected," the rep stated at the time.
Hear more on their complicated relationship in the video below.