United Kingdom, Aug. 19 -- Naomi Watts tearfully broke down as her son headed off to college.

The Mulholland Drive actress, 56, has Sasha Schreiber, 18, with her ex-partner Live Schreiber, 57, and documented her emotional farewell to the teen on her Instagram.

She posted photos of herself holding Sasha, with her head buried in his chest in one image and her standing alongside him with his luggage in another.

Naomi, who has co-parented Sasha with Liev, captioned the snaps: "Step #1."

She added: "Already (bawling)" - adding five crying face emojis to the message.

Naomi also tagged Sasha, who looked at the camera while wrapping his arm around his mother's shoulders.

Sasha wore a white T-shirt, baggy blue jeans and a chain in one image,...