The Academy graduate was initially called up to the Three Lions' Under-21s for the current international break but was promoted to the senior squad on Monday.
Mainoo, 18, will hope to play some part for Gareth Southgate's team in the friendlies against Brazil (on Saturday, 19:00 GMT) and Belgium (on Tuesday, 19:45 GMT).
If Kobbie does feature against the Selecao this weekend, it seems fitting that one of the players he idolised as a young child is a globally recognised maestro from that part of the world.
"Growing up, it was Ronaldinho," said the midfielder, when he was asked about his idol in a Q&A session with our Academy Under-8s, as part of his Playing with Freedom interview.