Pereira took to social media, posting a video of Dalot standing in the new Manchester City home shirt.
The defender was filmed giving a thumbs up to the camera before spinning around to show the number 20 on his back.
Pereira captioned the post: "soon on the pitch," showing excitement for the new signing.
Dalot is set to wear the number 20 shirt, which has graced the back of icons such as Robin van Persie and Ole Gunnar Solskjaer.
Dalot and Pereira have become close friends since his £17.4million arrival from Porto this summer, and the pair have been spending a lot of time together off the pitch.
His United career hasn't got off to the best start, after he suffered a knee injury at the end of his time at Porto.
Dalot is one of only three signings for Manchester United, along with Brazilian Fred and goalkeeper Lee Grant.
Tensions between chief executive Ed Woodward and Mourinho have been growing over the past months, as the manager gets more critical about the signing situation at the club.