A Hong Kong video showing schoolchildren wearing double masks while performing the flute has drawn ridicule on social media.
The ad, released by Hong Kong's Education Bureau, was posted ahead of China's National Day on 1 October.
It also comes after Hong Kong earlier announced a further extension in Covid restrictions, including masking.
It is one of the few remaining cities that have retained strict Covid measures since the pandemic struck.
The video, titled "Young China Says", which is centred around Hong Kong's youth, shows various schoolchildren performing a variety of artistic activities, including singing, calligraphy, martial arts and musical performances.
More than 400 schoolchildren from 41 high schools were invited to participate in the more than 5-minute-long video.
The clip was released by Hong Kong's Education Bureau on 21 September, in commemoration of China's national day on 1 October.
At the 45-second mark, the video shows two masked schoolgirls playing the flute side-by-side with what appears to be a secondary flap covering the musical instrument.
Users took to social media to pour ridicule on the ad.
"This city never fails to surprise me," tweeted South China Morning Post correspondent Jeffie Lam, adding the hashtag #maskingtilltheendoftheworld.
Another comment on Facebook said: "This is going to lead to so many jokes".
"This is the extent to which Hong Kong is scared of Covid," a Twitter user said.
The release of the video came as Hong Kong announced earlier this week that Covid restrictions would be in place until at least 5 October, including social distancing, and wearing masks in vehicles and specified public places.
Hong Kong has followed China's cue closely where Covid regulations are concerned - a move analysts say has battered the economy and caused Hong Kong's attractiveness as a business hub to wane.
Hong Kong also remains one of the few places in the world to still require travellers from abroad to quarantine on arrival, though officials are expected to make a highly-anticipated announcement on Friday easing the regulation.
China has adopted a strict zero-Covid policy since the pandemic