Has Cecilia Cheung let the cat out of the bag?
The Hong Kong actress, who turns 40 later this month, gave birth to her third son Marcus in November 2018, but has continued to keep the identity of his father under wraps.
She has two other sons - Lucas, 12, and Quintus, with her former husband, actor-singer Nicholas Tse, from their five-year marriage. They divorced in 2011.
Earlier this week, Cheung piqued the curiosity of netizens when she posted on China's Instagram-like app Oasis photos of the birthday celebration of Quintus, who turned 10 on Tuesday (May 12).
She was seen in one shot with Quintus only, and in another with her three sons. This was likely the first photo she has posted online of herself with all of them.
Some netizens zoomed in on Marcus, whose face was blocked by a picture of a cartoon duck. They noticed that his hair looked blond compared with that of his brothers.
They speculated that Marcus' father could be Caucasian, with some guessing that he could be a British engineer who was previously linked to Cheung.
Previously, a Singaporean F&B tycoon, a Chinese magnate, director Stephen Chow and even Tse were among those whose names came up in online talk about the identity of Marcus' father.
Cheung has so far remained tight-lipped and not responded to such online speculation.