Meunier famously pestered his club on Twitter ahead of their world-record purchase of Brazil superstar Neymar earlier this month, although it was PSG who picked up the thread with the Belgium international on this occasion.
Mbappe is reportedly on the verge of securing an initial loan move to Parc des Princes from the Ligue 1 champion in a deal that includes a compulsory purchase option of $A272.25 million to be triggered at the end of the season.
But as the Monaco star reported for training at Clairefontaine with his France international colleagues, it transpired PSG and Meunier were simply teeing up a birthday message for veteran midfielder Thiago Motta.
"The twittosphere stirs. What is going on @ThomMills," PSG tweeted, tagging Meunier's Twitter handle in the post.
"My fingers are burning. How can you tell me?" he replied, before telling his employers he had a possible tip-off.
"I have contacts on the @lequipedusoir," he said, referring to French sports news programme L'Equipe du Soir.
"First clue: letter M. Am I right?"
Confirming he was on the right track, PSG tweeted: "It's a good start indeed." Meunier then told his followers to expect an announcement at 12:30pm, French time.
One duly arrived, wishing Italy international Motta a happy 35th birthday, much to Meunier's entertainment.
Nevertheless, the expectation remains they will have a much-vaunted new team-mate very soon.