Betelgeuse may be a red supergiant star at only 400 light years away, but VY Canis Majoris, a red hypergiant at 3,900 light years, is the biggest star that we know of.
http://en.wikipedia.org/wiki/VY_Canis_Majoris
In this video you’ll see the size comparisons of our planets and various stars.
Betelgeuse is almost the same size as Antares A that is in video.
https://www.youtube.com/watch?v=HEheh1BH34Q
Antares: Betelgeuse’s Neglected Twin
http://www.aavso.org/vsots_alphasco
Oh I don’t know. Uhura sang about Antares.