In an article appearing in the January 2002 edition of Star Trek: The Magazine Volume 2, Issue 9 entitled "Who is that Alien?", the following information about the Betelgeusians, as taken from Fletcher's original background notes, added:
"The inhabitants of the real star Betelgeuse were seven-foot-tall humanoids who were actually descended from a race of leopard-like eagles. They had claw and bone-like structures like a condor, but walked upright."
The robe worn by the Betelgeusian ambassador was one of several costumes made from bolts of rare fabric, scavenged from storerooms around the Paramount lot, for the San Francisco crowd scenes. This particular fabric was originally hand-picked by Cecil B. DeMille for a 1939 production, and was made of silk thread with real gold and silver details. The estimated cost for the costume was at least US$10,000, probably making it the most expensive worn by an extra. (The Making of Star Trek: The Motion Picture, p. 129) The robe was auctioned as part of 2006's Profiles in History auction with an estimated sale price of US$1,000 to US$1,500; the final sale price was exactly US$1,000. 
Two additional Betelgeusian-related lots were included in the It's A Wrap! sale and auction, each containing an original Betelgeusean mask. The first mask sold for US$202.50 , the second, which also contained 3 masks, original jewelry and bronze-colored robe, sold for US$732. .
Betelgeuse (Alpha Orionis) was the name of a star in the Beta Quadrant. The primary was a Class M star. Magnitude of this star was -7. Betelgeuse was the name of a planet in the system. too, and had, by 2378, become a member of the Federation. (Star Trek: Star Charts, United Federation of Planets I & II)