'Kate's great-grandmother was Elizabeth Temple, the sister of my grandmother, Esther Temple.'

Hanselman, 51, remembers spending time with his grandmother in his home region of County Durham in northern England.

'She was very petite, very polite, very much a churchgoer and an amazing musician; she played piano. There was lots of happiness and laughter.'

On Friday, two billion people are expected to watch the royal wedding on television.

Hongkongers can watch a live telecast on TVB Pearl, which will stream the BBC coverage from 3pm to 8.40pm with a half-hour news break from 7pm to 7.30pm. At 8.40pm, it will show a one-hour documentary called William, Kate and 8 Royal Weddings.

An ATV spokesman said it was still awaiting confirmation on possible coverage.

Hanselman, who left the Hong Kong police force in 1997 and now runs a sustainable seafood import business, said the bloodline to British royalty was far-removed and changed very little.

'It's such a distant relationship, it doesn't mean much. The nice part about it is that they have actually identified my grandmother and she was such a special person. My daughter Hannah is quite excited and my friends are all taking the mickey out of me now because of this very vague relationship and calling me 'Sir Chris'.'

He said the family would watch the wedding at Hebe Haven Yacht Club as they had not been invited to Westminster Abbey.

'It will be nice to watch it with a crowd of people rather than sit at home. Of course it would have been nice to have been invited but it's unrealistic. If perchance an invite had come this way ...'

A self-confessed royalist, Hanselman came back from London two days ago and said the wedding frenzy had brought a ray of sunshine to a gloomy city.

'I don't go back to the UK very often because Hong Kong is home, but it does seem to have lifted the whole country. London was absolutely heaving, you couldn't get anywhere near Westminster Abbey. There was a real air of expectation and real happiness. With the debt crisis and the [problems with the] students, the Brits like this sort of thing.

'When you look at the pomp and the circumstance and the pageantry, we do it well. I believe that the Hong Kong people have good strong ties and memories of Britain, albeit it was a colony. They will get behind it.'

The British Chamber of Commerce, in conjunction with HSBC, will host a sold-out garden party on Friday at the Hong Kong Club.

The Dublin Jack, an Irish pub in Lan Kwai Fong, will switch all its five screens to the wedding coverage on Friday afternoon and host a private party, complete with Union Jack bunting.

The Globe in SoHo, a lively British pub, will put on her party heels for an event organised by female expatriate website Sassy Hong Kong with prizes for women who wear their best Kate Middleton-inspired outfits.

Jewellery store Accessorize is selling replica wedding rings for HK$85, and the Mandarin Oriental is offering fancy headwear just like those favoured by Kate. Supermarket chain Great has a range of teas, jams and shortbread from Duchy Originals, affiliated with Prince Charles' Charities Foundation.

Hanselman said he would love to meet his extended royal family members one day but he was not holding his breath.

'Would I like to meet Kate? I think it would be a very nice thing to do if perchance she came and said I'd like to see my third or fourth cousin removed.'