The pair is set to marry this summer and Harry will put his $40 million fortune on the line.
A source has revealed: "There was never any question in Harry's mind that he would sign a prenup.
"He's determined that his marriage will be a lasting one, so there's no need for him to sign anything.'
This will be the first wedding for Prince Harry, 33, but the second for Markle, 36.
The American actress divorced her first husband, American film producer Trevor Engelson, after two years.
And this prompted many Royal insiders to advise Harry to get a financial arrangement in place before he ties the knot.
But it seems that he is ignoring this advice because he believes that their marriage will be for life.
- 'Cruel': Thomas Markle Pleads With Estranged Daughter Meghan and Prince Harry to See His Grandchildren
- 'Unwanted' Prince Harry 'Blindsided' by Princess Diana Audio Revealing Charles' Disappointment Over His Birth
- Prince Harry Makes Somber Solo Trip to Honor Queen Elizabeth on First Death Anniversary Without Meghan Markle
Prenups are not legally enforceable in the UK, but are increasingly taken into account during divorce cases.
Harry was handed $13 million of the inheritance from his mother, Princess Diana, when he turned 30. He is said to have another $26 million of assets.
Meghan, 36, has amassed an estimated $5.2 million fortune from her successful acting career.
We pay for juicy info! Do you have a story for RadarOnline.com? Email us at firstname.lastname@example.org, or call us at (866) ON-RADAR (667-2327) any time, day or night.