Stephen Hawking's warnings of an alien invasion have prompted a vigorous defence of extraterrestrials by their most prominent Canadian fan.

Former federal defence minister Paul Hellyer, 86, believes not only that aliens have visited Earth but also that they have contributed greatly to human technological advances.

So he can't quite understand why the world renowned astrophysicist views them with such trepidation; Hawking recently warned that malevolent aliens could lead to the destruction of humanity.

To read the rest of the article, click here.