Although other characters from The Mouse That Roared (1959) appeared (Prime Minister Rupert Mountjoy and his opposition leader Benter) David Kossoff (Kokintz) was the only principal cast member of The Mouse That Roared (1959) who returned to play the same role in this movie.
In Margaret Rutherford's first scene, she appears on horseback, in military garb and wearing several medals. Close inspection shows that the medals are actually U.S. half-dollar coins, including a Ben Franklin (minted from 1948 through 1963, which was the year the movie was released), a Walking-Liberty (minted from 1916 through 1947), as well as two older half-dollars. Furthermore, the orientation of Franklin's face shows that the shot is actually inverted horizontally: Franklin's profile faces left, while on the actual coins, he faces right.
The American premier was held at Cape Canaveral, Florida, where cast members mingled with NASA astronauts.
Frankie Howerd: The then famous comedic actor, who is simply there for a moment playing himself, and then things continue. Contains a surreal blink and you'll miss it.