Ray Charles On Stage With Muhammad Ali (1971)

Who knows the story behind this surprising double bill of Ray Charles with Muhammad Ali, at the R.K.O. Albee Theater in Brooklyn, on 7 May 1965 1971?
In these years Ali's fights were telecasted in movie theaters. Was he here to promote that? 18 days later Ali would fight Sonny Liston for the second time (and beat him after 2:12 in the first round).

This is not to say that Muhammad Ali didn't have any stage presence (see YouTube for several examples; and in 1963 he released an album of spoken word (co-produced by Sam Cooke) on Columbia Records titled I am the Greatest).

(I think the bill is forgery;-!).

Update 20 September 2011:
This German newspaper article from 1971 has an interesting sentence, seemingly (a typo makes it hard to assess with certainty, BS) confirming two gigs by Ali with the Ray Charles Orchestra...

Update 28 November 2011:
No forgery, and 2 concerts indeed! The evidence is this ad from the New York Amsterdam News of 1 May 1971: