The result was a 2 1/2-minute music video that has attracted thousands of hits but garnered little acclaim for its music or credibility.

The video is called Rap Now 2010, a play on the Act Now campaign last year which used online media to promote the government's 2012 electoral reform package.

The video, filmed and recorded over one afternoon three weeks ago, appears to be an attempt to bridge a gap between Tsang and the younger generation using a genre synonymous with Generation Y: hip hop.

'We wanted to convey the chief executive's Christmas greetings to the community in a creative and cheerful fashion,' said Ronald Chan Ngok-pang, special assistant for the Chief Executive's Office.

'We had been impressed by MC Jin's artistic talent and found his music and style very suitable for our purpose. Therefore, we approached him and discussed the possibility of collaboration. MC Jin accepted our invitation; hence the song.'

MC Jin is a 28-year-old rapper who first gained fame in the United States as a 'battle MC', a rapper who verbally duels with another performer on stage with freestyle rhymes that rely on sharp wit and insults.

He was the first Asian-American to sign with major hip hop label Ruff Ryders after he won a rapping competition on US television in 2002. Jin relocated to Hong Kong in 2008 to further his career and has become a familiar face on local television.

For the video, staff from Tsang's office advised the rapper on what to say and MC Jin wrote and performed the song for free.

'We provided MC Jin with suggested themes, for example, a cheerful Christmas, and preliminary ideas - some of the most talked about subjects or 'hot words' of the year. On this basis, he wrote the lyrics and composed the music,' Chan said. 'In addition to Act Now, the song also makes reference to popular or frequently discussed themes like Facebook, education reform and banana throwing.'

By Friday, the video had received more than 860,000 hits with 3,600 'likes' and over 10,000 'dislikes'.

The video shows Tsang in his Government House office watching the clip on his laptop while MC Jin performs in the RTHK studios and in Tsim Sha Tsui East with Hong Kong's Christmas lights as a backdrop.

Mixed comments on MC Jin's Facebook and YouTube pages ranged from 'so catchy! I love this!' to 'people like the way you rap but probably not the message' and 'this video is communist propaganda'.

One Facebook fan posted: 'I know you can't read chinese so i will say it in English, you just killed your career because u rapped for a guy who is hated by most the hk ppl [sic].'

Another said: 'As a true fan of you, I support all decisions you've made, despite the fact the song has caused a lot of discomfort among many HK people.'

On YouTube, it was no less scathing: 'It is political propaganda. MC Jin now raps for the Hong Kong chief executive ... who works constantly against the democratic movements of Hong Kong people.'

Chan said that this was the first time Tsang had featured in a rap video and that the leader was pleased with the result. 'He is very excited about the end product and the enthusiastic responses.'

MC Jin's publicist said the rapper was filming a movie in Shanghai and was unavailable for comment.