HONG KONG • Maybe the maid who cared for the baby had to take off for an emergency.

Or maybe Cecilia Cheung felt it was not good to keep her seven-month-old son Marcus cooped up at home all the time.

Whatever the reason was, they ventured out of their home.

Which is why Hong Kong paparazzi managed to take the first photographs of the baby when mother and child were spotted for the first time in public recently.

But Cheung, 39, who has kept mum on the father's identity since she gave birth to her third son in November, took precautions to protect her family's privacy.

The actress turned up at her two elder sons' school in a car owned by her manager in a bid to evade attention.

Videos posted online showed her stepping out of the car carrying Marcus, but footage did not give a clear view of his face.

According to Sohu portal, Cheung, who was wearing dark sunglasses, showed up for a parents' day at the school with her younger brother Ronnie.

Cheung - whose elder sons Lucas, 11, and Quintus, nine, are from her previous marriage to actor Nicholas Tse - has yet to share a photo of Marcus on her social media accounts.

It is not known if the father has worked out an arrangement with her to keep the child under the radar. Sharp-eyed observers note that she is not hesitant to share online pictures of what her elder sons are up to.