The Royal Birmingham Conservatoire sent welcome letters to hopefuls who were actually on its reserve list.
The school, which is part of Birmingham City University and offers top courses in acting and music, said a "small number" of applicants on an acting course were mistakenly sent acceptance letters and blamed the blunder on an "administrative error".
Following the mistake, and after being contacted by the Express & Star, the Conservatoire has now decided to expand the course and admit those students who were sent acceptance letters in error.
It's understood some of the applicants were left upset after initially finding out they had missed out. One budding student was said to have been "very badly hurt by the situation" and had been celebrating with family and friends before being let down. They were later informed they would be accepted.
On its website the Royal Birmingham Conservatoire, which was founded in 1886 as the Birmingham School of Music and has around 1,200 students, describes itself as a "world-class institution providing exceptional training for the musicians, actors, stage managers and performers of the future".
A Birmingham City University spokesman said: "A welcome letter was sent to a small number of applicants on the reserve list for our acting course as a result of an administrative error.
"We have apologised to those affected for the confusion caused and are reviewing our processes to ensure that such a mistake does not occur again. On this occasion, we are also expanding provision on the course to accommodate these students and have contacted them individually to confirm our offer."