Before director Tim Burton chose Michael Keaton to play the Caped Crusader in 1989's Batman, he had offered the role to Pierce Brosnan. Surprisingly, Brosnan turned down the part even though the actor's only real claim to fame at that time was a starring role in a then-cancelled television series, Remington Steele (1982–1987).
"It was the beginning of these huge movies, and I just thought, Batman?" Brosnan told Details. "Batman held such an indelible place in my own childhood, but I said something flippant to Tim Burton like, 'Any guy who wears his underpants outside his trousers cannot be taken seriously.' So, yeah."
On a positive note, if he had taken the Batman role he may have not been able to take the role he was born to play in 1994: James Bond. As Captain Picard (Patrick Stewart) learned in "Tapestry," our past mistakes set us on the path to becoming the man/woman we are today.
Batman (1989) - Tim Burton directs; Michael Keaton stars as Batman; and Jack Nicholson stars as his arch foe, The Joker, in the first of the blockbuster Batman series of features. As the Dark Knight, defender of law and order in Gotham City, Batman treads the shadow zone between right and wrong, fighting with only his skill in martial arts and his keenly honed mind to defend the innocent and to purge the memory of his parents' brutal murder--always keeping his true identity as millionaire philanthropist Bruce Wayne a closely guarded secret.