Bash - check number of arguments

Question

In my script I want to check if 1 or 2 arguments have been passed but my if statement is not working the way I expect it to.

#!/bin/bash

if [[ $# -ne 1 ||  $# -ne 2 ]];
then
   echo "Needs 1 or 2 arguments"
exit 1
fi

hello() {
   echo "Hello world"
}

case "$1" in
       hello)
            hello
            ;;
       *)
            exit 1
esac

If I run

./script.sh hello

my If statement returns true and I get the echo statement "Needs 1 or 2 arguments". What am I doing wrong?