Not counting seeing someone at their concert, and counting only people with a Wikipedia page...
I've met The Hon President Jasper Tsang GBM JP BA MEd CertEd (HK), then-legislator and president of the Hong Kong legislature, and a founder of the DAB, now the largest party in the Legislative and District Councils of Hong Kong, at an event for him to meet some Oxonians.
I've met honorary dame and honorary fellow of SOAS The Hon Secretary Anson Chan GBM GCMG CBE JP, the first female and non-white, non-Japanese head of government of Hong Kong, and a former legislator, at a performance of MacBeth.
I've met His Excellency Ambassador Duncan Taylor CBE MA (Cantab) of the United Kingdom of Great Britain and Northern Ireland to the United Mexican States, son of His Excellency Ambassador Sir Jock Taylor KCMG and grandson of His Excellency Ambassador Sir John Taylor KBE CMG, at the UK Alumni Awards at the British ambassador's residence.
I've met The Rt Hon His Excellency The Lord Christopher Patten CH PC MA (Oxon), the Chancellor of Oxford University, advisor to His Holiness The Pope, former chairman of the Conservative and Unionist Party, former European commissioner, former member of parliament, former chancellor of Newcastle University, former chairman of the BBC Trust, former president of the Legislative Council of Hong Kong, former chancellor of the Duchy of Lancaster, former Secretary of States for the Environment, former minister for Overseas Development, the last British governor of Hong Kong, at an event of the Oxford University Conservative Association.
I've met The Rt Hon Secretary Nicky Morgan PC MP MA (Oxon), the chair of the Treasury Select Committee, former Education Secretary, former Minister for Women and Equalities, former Minister for Women, former Financial Secretary to the Treasury, former Economic Secretary to the Treasury at the Oxford Union.
I've met Professor Mark Bray BA (Newscastle) MSc PhD (Edin), the Chair Professor of Comparative Education in the Comparative Education Research Centre of The University of Hong Kong, former Dean of Education, former Director of UNESCO-IIEP. former President of the World Council of Comparative Education Societies.
I've met Professor Jonathan Michie of The University of Oxford, the Director of its Department for Continuing Education, son of Professor Dame Anne McLaren and Dr Donald Michie, who worked with Dr Alan Turing during the Second World War.
I've met Walk of Famer, world champion, Paralympics gold medalist Grace Clough MBE at a Guest NIght's Dinner at Kellogg College Oxford.
At the same event, I also met world champion Olympics gold medalist Paul Bennett MBE.
I've met Kelly Clarkson at an HMV autograph event. A friend wanted her autograph too and asked me to get one for him, so I got it for him first, then I asked Kelly if I could get one for myself. The staff next to her took away my album saying only one is allowed, then she took my album back and signed it.
There should be some other people I don't remember.
Voice of the truth here!!