Baby Love for Liev & Naomi

Liev Schreiber and a very pregnant Naomi Watts  looked oh-so-in-love at the Nov. 18 Milk after-party in NYC.

"He was rubbing her leg and making sure she was warm," an onlooker tells OK!. "They couldn't stop smiling and touching her belly."

Liev and Naomi are already parents of 16-month-old Alexander, and their latest addition is due any day. Naomi told the partygoer, "I'm almost there!"

The couple have been together since 2005 and welcomeed Alexander in 2007, but have decided not to tie the knot for now.