United and Juve agreed terms over a fee for the France international last week.
Rabiot's mother and agent, Veronique, has been negotiating contract terms directly with United football chief John Murtough in recent days.
And this morning, a video has begun to circulate on social media of a conversation between the Frenchman and a fan.
"I'm here with the great Rabiot, a Juventus player, in England. I wish you all the best. Farewell," said the fan.
"Thank you, goodbye," replied Rabiot.
The 27 year-old is currently in his third season with Juve.