Justin Bieber is proud of his new mustache. The 19-year-old joked about his new look in a newly released teaser for his new Believe film. The "Heartbreaker" singer previewed a new clip for the movie via Twitter on Friday, Oct. 11.

"I keep my promises. U got #heartbreaker to #1 so I owe u #filmfridays..Here is your first #filmfridays. "The #stache lol," he wrote to his 45 million followers.

In the clip, the "Boyfriend" singer isn't shy about poking fun of his new stache after it was pointed out by his manager Scooter Braun. "Speaking of grown men, I'm drinking coffee right now," Bieber joked. (The young star first debuted the wispy new facial hair at NYC Fashion Week in early September.)

Bieber has definitely grown up since his "Baby" days, as pointed out by both his mentor Usher and mom Pattie Mallette. "As a 19-year-old, Justin is now becoming his own man," the "Yeah" entertainer says in the preview.

Mallette adds: "I think it's hard for parents to let go, but its really exciting too to see him maturing."

Bieber released his first documentary, Justin Bieber: Never Say Never, in 2011. His upcoming Believe film hits theaters Christmas Day.