"The kids are lovely," he said. "I left to do a pantomime but I ended up coming back because I love it so much."
Mignonne Cox, owner of the academy, said the students were very proud of their teacher's star turn.
"He's absolutely fantastic," she said. "He's been teaching for us for about a year now.
"How he is on Britain's Got Talent is exactly how he is in class. The children absolutely adore him.
"All the students are really, really excited. I'm so happy for him."
Yet the idea of being a comedian had never even crossed Philip's mind until he appeared in pantomime last Christmas with former Britain's Got Talent winner, dancer George Sampson.
"I never thought of myself as a comedian really, but people tell me I'm funny," said Philip, who lives in Shepperton.
"I used to muck around with my friends and a camera when I was younger, but nothing serious.
"I did my voices for the cast of the pantomime and George told me I should go for it, so I did."
The first time he performed his comedy impressions act in public was at his audition for the show, filmed in February but aired last weekend.
Philip got four "Yes" votes from the judges, after impersonating celebrities ranging from former EastEnders star Natalie Cassidy to presenter Lorraine Kelly and singer Stacey Solomon.
Simon Cowell told him, "You are a naturally funny guy", while Amanda Holden said: "You had us laughing before you even did anything."
Philip said he watched Saturday's broadcast "cringing behind the sofa" with proud family and friends.
He said: "It was scary. I was absolutely petrified, especially with Simon. I was like, 'Oh my god, it's Simon Cowell!'
"The kids in my class were so excited to see it."
He added: " People have started recognising me. It's really weird. It doesn't feel real."
