Prince Salman bin Hamad Al Khalifa sent his regrets to Prince Charles after questions emerged over the British monarchy's decision to invite a member of Bahrain's Sunni ruling family, which has waged a wide-ranging crackdown against Shiite protesters calling for more freedoms.
Bahrain's rulers have imposed martial law and are backed by a Saudi-led military force to try to quell the uprising. At least 30 people have died in Bahrain since mid-February, including four who died while in official custody, and many well-known activists and lawyers have been imprisoned.
The news helped to avoid a potentially awkward situation during the April 29 wedding. Campaigners in Britain complained when palace officials said Saturday that the prince was attending the nuptials, and some petitioned Foreign Secretary William Hague to revoke the invitation.
Prince Salman said he was "saddened and troubled" by British reports about his attendance.
"While these (media reports) have certainly highlighted a number of significant issues currently facing the Kingdom of Bahrain, they have fundamentally misrepresented my own views, outlook and position on recent events and thus, clearly sought to involve my potential attendance as a political proxy for wider matters involving Bahrain."
A Buckingham Palace spokesman confirmed that it was informed Sunday about the prince's decision.
The prince said Bahrain has the highest respect for Britain's royal family, and that he wished William and Middleton "all good wishes for Friday and every possible happiness for the future ahead."
Al Khalifa was among more than 40 foreign royals invited to the wedding. Other foreign royals who are attending include kings, queens, princes and princesses from countries including Denmark, Norway, Spain, Saudi Arabia, Thailand, and Swaziland.
The royals will mingle with a handful of celebrities, including soccer star David Beckham and his wife Victoria, singer Elton John, director Guy Ritchie and Mr. Bean actor Rowan Atkinson.
About 1,900 people were invited to the Westminster Abbey ceremony.