A Nod to the Original
Most parodies make an effort to give the nod the original as a matter of respect. That’s why Brooks figured he should include the legendary Western actor John Wayne in the movie. And word has it that the two met by chance on the Warner Brothers lot. John told Mel that he heard about his movie. So Mel wrote a short bit for Wayne, but John actually declined the part, saying “Naw, I can’t do a movie like that, but I’ll be first in line to see it!”

Source: IMDB
The legendary comedic actor Gene Wilder started collaborating with Mel Brooks on the movie ‘The Producers.’ When Mel then asked Gene to be in ‘Blazing Saddles,’ Wilder negotiated a deal. Gene said he would be in his film if he would look over a script he started writing which he hoped to make into a movie. Mel agreed. The script was for the eventual Oscar-nominated film ‘Young Frankenstein.’
See, next, how Brooks manages to insert slapstick comedy in his movies…