The 17-year-old singer looked delighted with his waxwork, despite the fact the model only bears a slight resemblance to the teen idol.
"It's pretty incredible to see. I'm taller but this was a point in time. It looks awesome, thanks very much," the Daily Mail quoted him as saying.
The pop star asked his mother to come up on stage, saying to her: "It [the sculpture] doesn''t have any facial hair."
He then gave the wax work a hug, but refused to kiss it in front of photographers.
He later added: "I''m just taking him home with me!"
Bieber worked closely with the team who created his waxwork, giving sittings in New York last year.
And stylists teamed up with the singer's personal hair stylist to ensure his once legendary hairstyle was the exact replica of the original cut.
The unveiling was broadcast live for the first time in the museum''s history on a special website revealed by Bieber on the Twitter website earlier in the day.
Replicas of the teenager were simultaneously unveiled at Tussauds attractions in Amsterdam and New York.
The London and Amsterdam models are identical but the New York wax work wears an outfit donated by the star.