The arrival of the couple's first child, who is yet to be named, changes the line of succession for the throne.
Prince Harry and Meghan's son is seventh in line to the throne, meaning that Prince Andrew, the Queen's second eldest son, is now eighth in line.
The first few members of the royal family in the line of succession remain unchanged.
First in line is Prince Charles, who became the longest-serving heir apparent in 2017.
The Prince of Wales beat a previous record of 59 years, two months and 13 days set by his great-great-grandfather King Edward VII.
Prince Harry's older brother, the Duke of Cambridge, is second in line to the throne.
The Duke of Sussex is sixth in line, which subsequently places his newborn son in seventh place.
In April 2018, Princess Charlotte made history as the first female member of the royal family to retain her claim to the throne following the birth of her younger brother.
Prior to the Succession to the Crown Act of 2013, a female royal’s claim to the throne would have been diminished by the arrival of a younger brother.
However, as stated by the legislative act when it was passed six years ago: "In determining the succession to the Crown, the gender of a person born after 28 October 2011 does not give that person, or that person’s descendants, precedence over any other person (whenever born).”
Following the announcement of his son's birth, Prince Harry addressed the press in Windsor.
The beaming father said that watching his wife give birth was an "amazing experience".
"I’m very excited to announced that Meghan. and myself had a baby boy early this morning, a very healthy boy," he said.
"How any woman does what they do is beyond comprehension.
"We're both absolutely thrilled and so grateful for all the love and support from everybody out there. It's been amazing."
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