There have been at least five Omen films. The Omen(1976), Damien: Omen II (1978), Omen III: The Final Conflict (1981), Omen IV: The Awakening (1991) (TV) and The Omen (2006), which is a remake of the first movie.
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Harvey Stephens
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No, Tubular Bells is better known as the theme song to The
Exorcist, not The Omen. I checked and it is not listed on the
soundtrack of either the 1976 nor the 2006 version of The Omen.
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It is considered the 14th scariest film by Entertainment Weekly.
It was considered very scary at the time of its release.