"There was no way, the studio was going to get around putting Ledger in the main TV spots," Thilk said. "I imagine they said, 'Let's not avoid the elephant in the room; he's a strong part of the movie, an amazing actor; it's going to be weirder if we take him out of the campaign than just leave him in.'"
Zeitchik said the studio was also aided in its promotion by the fact that Ledger had already completed filming "The Dark Knight" before he died.
"This is a case where the movie was done," he said. "It's the easiest of all situations. It's a complete role, by all accounts, that he's very good in. It doesn't seem as tricky a situation as it could have been."
In any case, early reviews of the film are excellent and industry watchers are predicting a blockbuster.
"It will open strong and continue to build," box office expert Paul Dergarabedian told ABCNews.com after viewing a screening. "This is not going to be a flash in the pan. All the acting is great, the script is excellent, the action set pieces are visually stunning and complex. The movie resists any categorization."
But it is Ledger's performance that is generating the most buzz and has some saying he deserves an Oscar nod for best supporting actor.
"I was blown away not only by the movie but his performance," Dergarabedian said. "This is a true psychopath, a remorseless, incredibly evil character. But when he's on screen, you cannot take your eyes off him. And when he's off screen, you can't wait till he reappears on screen."
"It's going to be the stuff of movie legend," he added. "There was this idea before that maybe he was a long shot to get a nomination. Now, if he were not to get a nomination, that would be a surprise."
Creating an Oscar campaign for Ledger, however, could be tricky, according to Thilk.
"If I were Warner Bros, I would keep my head so low you couldn't see it over my desk," he said. "You're only going to look like an opportunist. There's no way you're going to mount a best supporting actor campaign that has any vim or vigor and not look like you're picking the bones. The best thing to do is submit his name and leave it alone. Let the performance speak for itself."
Only six actors have ever been posthumously nominated: Jeanne Eagels for "The Letter" (1928-1929); James Dean for "East of Eden" (1955) and "Giant" (1956), both of which became hits despite the studio's concern; Spencer Tracy for "Guess Who's Coming to Dinner" (1967); Peter Finch for "Network" (1976); Ralph Richardson for "Greystoke: The Legend of Tarzan" (1984); and Massimo Troisi for "Il Postino" (1955). Only Finch received an Oscar.
Gehring, who writes a column called The Reel World for USA Today magazine, said in the past, Academy voters might have nominated deceased actors in order to recognize them, but they were unlikely to give the award to someone who couldn't be there to receive it.
He said Katharine Hepburn always said that she won the best actress Oscar for "Guess Who's Coming to Dinner" because Academy voters really wanted to honor Tracy, her longtime lover.
Today, there's a greater likelihood that Ledger could not only receive a nomination but win, Gehring said.
"His death might even help, because the pendulum has swung so far the other way," he said.
Ultimately, it will be his performance, not his death, that leaves an impression on Academy voters, Dergarabedian said.
"Really, the movie honors him," he said. "It celebrates what a great actor he was. It would be one thing if it was a horrible performance and a bad movie. But if you're a Batman fan, you have to see it and, if you're a Heath Ledger fan, even more so."