Prince Harry of Wales
The most famous spare heir of all! Prince William's younger brother—military man and beloved rambunctious bachelor—is the second-born son of Prince Charles and the late Princess Diana. Upon the arrival of Will's second child, Harry drops a spot to fifth in line for the British throne.
Princess Eugenie of York
Princess Beatrice's little sis is the second child of Prince Andrew (Queen Elizabeth II's third child) and Dame Sarah "Fergie" Ferguson. Upon the birth of her new cousin, she's eighth in line to the British throne.
Zara Phillips
Queen Elizabeth II's second-eldest grandchild, the regal equestrienne is the second child of Princess Anne (herself a spare heir as king-to-be Prince Charles' younger sister) and her first husband, Mark Phillips. Peter Phillips is Zara's older brother. Because Anne's younger brothers, Prince Andrew and Prince Edward, have two kids apiece, Zara and Peter are behind their cousins in line for the throne.
Princess Margaret
Queen Elizabeth II's younger sis, whose divorce and multiple love affairs (well, anything more than one is usually considered scandalous by royal standards) was quite the trailblazing royal back in the day.
Princess Anne
Queen Elizabeth II's second child was third in line to the throne at birth, behind only her mum (who succeeded dad King George VI) and elder brother, Prince Charles. After the arrival of two younger brothers, their kids and then their their kids... She's currently 11th and will be 12th after Prince William & Duchess Kate's second child arrives.
Princess Alexia of the Netherlands
The young lady on the left is the middle daughter of King Willem-Alexander and Queen Máxima and is second in line to the throne after big sis Catharina-Amalia (middle). That's younger sis Ariane on the right. Meanwhile, we want the number of their tailor.
Prince Gabriel of Belgium
The adorable young lad is the second child of King Phillippe and Queen consort Mathilde, and he's next in line after his older sister, Princess Elisabeth, Duchess of Brabant.
Prince Abdul Malik
Sultan of Brunei Hassanal Bokiah's second-eldest son with wife No. 1 is is behind his older brother, Crown Prince Al-Muhtadee Billah, in the order of succession—but being second didn't stop him from getting married in first-rate fashion.
Victoria Federica de Marichalar y Borbón
This adorable 12-year-old, the second of Princess Elena of Spain's two daughters, is fifth in line to the throne.
Prince Nikolaos of Greece and Denmark
He's the third child of King Constantine II of Greece and Anne-Marie of Denmark, but the second son and therefore before older brother Crown Prince Pavlos but ahead of their older sis, Princess Alexia.
Infanta Sofía of Spain
Born April 29, 2007, King Felipe VI and Queen Letizia's younger daughter is second in line to the Spanish throne behind big sister Leonor, Princess of Asturias.
Princess Benedikte of Denmark
The second daughter of King Christian IX and Ingrid of Sweden is currently 11th in line to the throne, but big sister Margrethe II is the reigning Queen of Denmark, the country's first female ruler in roughly 600 years. A constitutional amendment passed in 1953 paved the way for Margrethe to succeed their father, King Frederik IX.
Prince Carl Philip, Duke of Värmland
The relentlessly handsome Swede is the second of King Carl XVI Gustaf and Queen Silvia's three children, and he's third in line to the throne after big sister Crown Princess Victoria and her daughter, Princess Estelle (his niece and goddaughter...aw...)