Shia LaBeouf "dropped the ball" on 'Indiana Jones and the Kingdom of the Crystal Skull'.

The 23-year-old actor - who is currently at the Cannes Film Festival promoting project 'Wall Street: Money Never Sleeps' - admits his turn as Mutt Williams in 2008's 'Indiana Jones' sequel was not as good as it could have been, the Los Angeles Times reports.

He said: "I feel like I dropped the ball on the legacy that people loved and cherished.

"You get to monkey-swinging and things like that and you can blame it on the writer and you can blame it on Steven Spielberg, who directed. But the actor's job is to make it come alive and make it work, and I couldn't do it. So that's my fault. Simple."

Shia is also says the film's leading man Harrison Ford was not happy with the finished product, which took in $786.6 million at the box office on its release.

He said: "We had major discussions. He wasn't happy with it either. Look, the movie could have been updated. There was a reason it wasn't universally accepted."

"We need to be able to satiate the appetite. I think we just misinterpreted what we were trying to satiate."

Shia is currently filming 'Transformers 3', due for release in 2011.