Tom and his wife Lara were then said to be "punished" for voicing their concerns about the relationship and were not invited to Harry and Meghan's evening wedding reception at Frogmore House.
200 guests reportedly attended the evening soiree hosted by Prince Charles including Hollywood A-listers George and Amal Clooney and Oprah Winfrey.
However, Harry and Tom's feud was resolved after Lara's mother passed away and a report by The Sun revealed that when Harry heard the tragic news "it really hit a nerve."
Friends said that Lara raised money for Heads Together, one of Harry's charities, and the prince donated a significant sum.
“Lara has raised money to support research into mental health and Harry decided to let bygones be bygones.”
Tom, who now works as a banker and was one of the friends present during Harry's Las Vegas romp in 2012, wasn't the only one concerned Harry was rushing into his relationship with Meghan.
According to sources quoted in the biography, Prince William told his younger brother “Don’t feel you need to rush this. Take as much time as you need to get to know this girl.”
But it was the use of the phrase "this girl" that really irked the red-headed royal.
"Harry could see through William's words. He was being a snob," a source close to Prince Harry says in the book.