Heath Ledger went to great lengths to get into character as the Joker. He locked himself in a motel room for 6 weeks to develop the Joker's laugh and voice. He also designed the Joker's makeup himself using white clown makeup from a drugstore. While filming The Dark Knight, some of Ledger's reactions and gestures like clapping in his cell were unscripted but kept in because the director felt it fit the character well. Ledger also kept a diary in character as the Joker to help him get into the Joker's mindset.

1. 11 THINGS
YOU
PROBABLY
DIDN’T
KNOW
ABOUT
HEATH
LEDGER –
THE JOKER

2. 1- He was the only
actor to win an
Oscar for the
portrayal of
‘Joker’ and also
the only actor to
be nominated for
acting skills from
the movie
‘Batman’.

3. 2- While filming a
scene in the
movie “Brokeback
Mountain” in
2005, Heath
Ledger almost
broke the nose of
Jake Gyllenhaal
during a kissing.

4. 3- He had designed
the look of the
“Joker” himself with
the help of some
white clown makeup
and cosmetics from a
drug store. Once
approved, the
makeup artists were
responsible for
replicating it for the
entire production.

5. 4- To prepare for
the role of joke
Heath Ledger
locked himself in a
motel room for 6
weeks and
developed
the sadistic
laughing sound
and the joker’s
voice.

6. 5- During the
hospital scene,
when The Joker
is dressed as a
nurse, his name
tag reads Matilda,
after Heath
Ledger’s
daughter Matilda
Ledger.

7. 6- As the Joker
Heath Ledger
scared Michael
Caine (Alfred)
so bad that he
forgot his
lines.

8. 7- The line “Don’t Shoot the
Messenger” in “The
Imaginarium of Doctor
Parnassus” was improvised
by Ledger as he did most of
the comedic lines. Johnny
Depp who later completed
Ledger’s role suggested
this same line without
knowing that it was already
spoken by the late actor.

9. 8- The Hospital
explosion scene
in “The Dark
Knight” has a
pause in between
which was
scripted but the
reaction of
Ledger was not
scripted.

10. 9- The clapping the
Joker does while
in his cell when
Gordon is
promoted was
unscripted, but
Christopher Nolan
told the crew to
continue filming
and the scene
made it into the
film.

11. 10 – Heath Ledger
kept a Joker Diary. In
it he wrote as the
Joker and included a
list of things he
believed the Joker
would find funny
including blind
babies, geniuses
with brain damage,
and sombreros.

12. 11- Heath Ledger would skateboard
on the set while he was wearing
the costume and full makeup of
The Joker. He was not in the
character while he did this but was
being his regular self
*You can watch him doing skateboard
https://youtu.be/u0-Skvzil8k