A Royal Duty is based on his experiences with Diana, Princess of Wales and letters allegedly to and from her.
The royal household was bracing itself for any more revelations in A Royal Duty, based on the former servant's time with Diana, Princess of Wales.

Rate the textual similarity of these two sentences on a scale from 0 to 5, where 0 is "no meaning overlap" and 5 is "means the same thing".
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