Alec Baldwin and his famous brothers are mourning the loss of their aunt following her death on Sunday (07Apr13).

The 30 Rock actor revealed the sad news to fans on Monday (08Apr13) after Louise Greacen, sister of Baldwin matriarch Carol, passed away.

In a post on Twitter.com, Baldwin writes, "My mother's sister, Louise Greacen, one of my favourite relatives, passed away yesterday. She will be missed."

Greacen was also aunt to Baldwin's actor brothers, Daniel, William, and Stephen.