We love a good royal get-together, when all the world's monarchs (and there are more than you'd think) throw on their best crowns and gather together for some awesome photo opps.

We usually have to wait for a royal wedding for such moments. But thanks to Queen Elizabeth II's Diamond Jubilee, the British royal family are partying it up with their international peers at today's Sovereign Monarchs Jubilee Lunch in Kensington.

Who flew in to England to fete Queen Elizabeth II's sixtieth year on the throne? Almost everyone. Queen Anne Marie and King Constantine of Greece, King Albert and Queen Paola of Belgium and the super adorable Empress Michiko and Emperor Akihito of Japan made the trip, as did royals from Denmark, Luxembourg, Norway and Jordan (Queen Rania!).

A few guests are a bit more notorious. King Mswati III of Swaziland and King Hamad al-Khalifa of Bahrain, as well as royalty from Kuwait, Qatar and Saudi Arabia, made the list, stirring up some controversy over their countries' human rights abuses.

"The queen has invited royal tyrants to celebrate her Diamond Jubilee," human rights activist Peter Tatchell told CNN. Anti-monarchy groups concerned with democracy also voiced their opposition. "The British people strongly support the struggle for democracy in the Middle East and around the world -- this is a catastrophic error of judgment that has already prompted a fierce backlash," Graham Smith, chief executive of anti-monarchy group Republic, told The Guardian.

And then there were the notable absences. Queen Sofia of Spain declined her invitation over a planned trip by Prince Edward and Sophie, the Countess of Wessex, to Gibraltar, a UK territory also claimed by Spain.

But for those in attendance at Windsor Castle this afternoon seemed to be having a fine time. Catherine and Princess Charlene, both clad in springy pastels (Kate's by Emilia Wickstead), chatted with drinks in hand; and Prince William and Prince Harry enjoyed a few laughs nearby.

Check out the royals in all their glory, below. How good does Charlene's newly-shorn hair look? What do you think she and Kate talked about? Did anyone get day-drunk? The mind reels.

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  • Catherine, Duchess of Cambridge, Prince William, Prince Albert II & Princess Charlene of Monaco

    (AFP photo)

  • Catherine, Duchess of Cambridge, Prince William, Prince Albert II &Princess Charlene of Monaco

    (AFP photo)

  • Prince Harry, Prince William & the Duchess

    (Getty photo)

  • Prince Harry, Prince William & the Duchess

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  • Kate & Prince William

    (AFP photo)

  • Princess Eugenie, Princess Beatrice, Princess Charlene & Prince Albert II of Monaco

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  • Queen Paola & King Albert of Belgium

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  • Emperor Akihito & Empress Michiko of Japan

    (AFP photo)

  • Princess Lalla Meryem of Morocco

    (AFP photo)

  • King Mswati III of Swaziland & Inkhosikati LaMbikiza

    (AFP photo)

  • Prince Albert II & Princess Charlene of Monaco

    (AFP photo)

  • King Abdullah II & Queen Rania of Jordan

    (AFP photo)

  • King Letsie III of Lesotho & Queen Mesenate Mohato Seeiso

    (AFP photo)

  • Princess Charlene & Prince Albert II of Monaco

    (Getty photo)

  • Queen Anne-Marie of Greece & Qatar's First Lady Sheikha Mozah

    (AFP photo)

  • Emir of Qatar Sheikh Hamad bin Khalifa Al Thani & Qatar's First Lady Sheikha Mozah bint Nasser al-Missned

    (AFP photo)

  • Queen Beatrix of the Netherlands & Queen Elizabeth

    (Getty photo)

  • Princess Lalla Meryem of Morocco & Queen Elizabeth

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  • Henri, Grand Duke & Maria Teresa, Grand Duchess of Luxembourg

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  • Crown Prince Alexander II & Princess Katarina of Yugoslavia

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  • Queen Anne Marie & King Constantine of Greece

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  • Bahrain's King Hamad bin Issa al-Khalifa & Sheikha Sabika bint Ibrahim al-Khalifa

    (AFP photo)

  • Queen Elizabeth II & her Royal guests

    (AFP photo)