Gnabry has notched up 12 goals and nine assists in all competitions, establishing himself as the undisputed successor to the departing Arjen Robben and leading Bayern's remarkable comeback in the Bundesliga title race.
Having signed for Bayern in 2017, Gnabry initially impressed on a loan spell at Hoffenheim before coming back to prove himself in Munich this season.
Bayern president Hoeness has admitted that the 23-year-old's fabulous form has caught many by surprise, even within the club.
"We thought 'let's get him back here and see if he can play in the odd game'," said Hoeness in an interview with Kicker magazine on Tuesday.
"Now he is a first-team regular, is great fun to watch and is the biggest surprise of the season, in a positive sense."
Having emerged as an exciting young talent at Arsenal several years ago, Gnabry's promising career appeared to have stalled when he left the Gunners in 2016.
Yet he has flourished since then, going from strength to strength in spells at Werder Bremen, Hoffenheim and Bayern in the last three years.
He has scored eight goals since December, helping Bayern overturn what was a nine-point deficit and overtake Borussia Dortmund at the top of the table.
On Wednesday, he faces former club Bremen in the semi-finals of the German Cup, as Bayern look to complete a fifth domestic double in this decade.