Along with her message she attached a sweet black and white photo of her son, 23-year-old William Stevenson, cuddling his newborn as both of the boys sleep.
Unable to contain her excitement, Alley also shared a solo shot of baby Waylon hours later.
“Just GOTTA send one more…proud Gammy,” she captioned the photo.
Alley and her ex-husband Parker Stevenson adopted William in 1992.
Now that William is a parent himself, he and his mother can share in the joys of parenthood — the part of her life, Alley takes the most pride in.
“My best quality is that I’m a good mother,” she told WHO in 2006.