The newly released messages appeared to show the Duke had previously struck up a friendship with the Mail on Sunday’s former diary editor.
Griffiths, 40, now editor at large, had told the High Court earlier in March, that she had socialised in some of the same circles as the younger royals.
She described how Prince Harry “friended” her on Facebook in 2011 and sent her his mobile number before they exchanged messages online. They also attended an all-night party the following June and texted each other the next morning.
When the Duke gave evidence, he said he had “no idea” whether she moved in his social circles and insisted he had only met Griffiths once, at a party hosted by their mutual friend Arthur Landon.
When he realised she was a journalist, he said he “had words” with his friend “and that was that”.
But the string of Facebook messages, seen in full for the first time, appear to suggest a slightly different story.
The Duke sent the first message, on December 4, 2011, telling Griffiths: “It’s H,incase u were confused by name and picture!!! X”.
Griffiths, who at the time was the paper’s deputy diary editor, replied: “Hello Mr Mischief… Did you get home OK slash did you actually find your car and did you beat Arthur down the motorway more importantly?!”
She added: “What a fun weekend of naughtiness – can’t we all get up to no good in the countryside every weekend damn it?? Smooches, CG String. Xxx.”
The Duke replied that it was “without doubt the best of those weekends I’ve been to”.
He added: “What a crowd. Never laughed so much in 24hrs!! Mr mischief? How do I get that title ... l was surely no worse than anyone else!!”
He said he had “Serious withdraw symptoms still” but that he had been forced to “make polite conversation with strange people at a dinner last night.begging them for money for charity! Really fun.not.”
The Duke told Griffiths: “Hope work isn’t too dull wherever u are?!”
Griffiths suggested a team reunion and referred to the lack of banter “on the group email front!”
Just over 10 days later, on December 15, the Duke told the journalist she had “missed a good party last night”.
Then on January 22, 2012, Griffiths replied, referring to the Duke as “H Bomb” and telling him: “We missed you so much at Arthur’s last week”.
The Duke responded: “I WISH I was there sugar but unfortunately stuck in Cornwall doing Army stuff :( Otherwise I would have been there playing and then drinking u under the table,obvi!!”
He added: “Just wish I could have been there ... especially now that you’re there! Dou ever work?!!.... Hope you’re really well Griff ... Miss our movie snuggles!! I’m off comms all week incase u think I’m being rude,keep me posted xxx xxx xxx.”
Griffiths told the court that in June 2012, she and Prince Harry had attended a house party hosted by Landon, which she remembered because they thought it was “quite funny” that the Duke had stayed up all night before having to go to a Trooping the Colour event the next morning.
Call data is said to show a call between the two at 2.50am, and three text messages exchanged between them the next morning.
At the High Court on Tuesday, barristers for each side submitted closing written arguments totalling 392,164 words.
Antony White KC, for Associated Newspapers, criticised the “speculative nature” of the claim, brought by seven high-profile figures including Sir Elton John and Baroness Lawrence, and the “frankly desperate” allegations put repeatedly to “respectable journalists”.
David Sherborne, for the claimants, said each of his clients should receive a “very substantial award of damages”.
The judge said he would be “toiling away on the judgment” full time after Easter but gave no indication about how long the task might take.
Sign up to Herald Premium Editor’s Picks, delivered straight to your inbox every Friday. Editor-in-Chief Murray Kirkness picks the week’s best features, interviews and investigations. Sign up for Herald Premium here.