Hong Kong veteran singer Alan Tam managed to shed almost 9kg in a month due to frequent workouts.

However, it looks like the Cantopop icon may not be able to keep up his efforts as he turns 70 on Sunday (Aug 23).

On Tuesday, he posted on Weibo two photos of himself cutting a birthday cake topped with the words: "Happy birthday, Principal".

The singer - known affectionately as Principal Tam due to his stature in the industry - wrote in Chinese: "I received my first birthday cake from Duncan who sent it on behalf of Universal Music yesterday.

"In the past, I would have received more than 20 cakes from early July till now, but with six days to go, I believe I will be stuffed with cakes in the next two days.

"It looks like my weight will bounce back after I've lost almost 9kg in the last four weeks."

But it appears he will not be giving up without a fight: he went for a jog on Wednesday.

He posted three photos of himself on Weibo after completing his runs which he described as good and refreshing.

Tam closed his Instagram and Facebook accounts in July after he received flak and criticism for publicly backing the Hong Kong police and attending a pro-police rally in June 2019 during the anti-government protests.

He was slammed in February after he was seen, along with several other Hong Kong stars including Jackie Chan and Eric Tsang, at a banquet with Hong Kong police officers. They drew further ire from netizens as they were not wearing masks despite the Covid-19 pandemic.