Expectations are high for Joss Whedon's "Avengers: Age of Ultron. It has been confirmed that Whedon started filming in South Africa just two months ago, and already fan-shot images and videos from the set have emerged online.

"Age of Ultron' takes place in the aftermath of previous Marvel films like 'Captain America: The Winter Soldier', which means that set leaks could end up revealing major details about the upcoming film, in addition to the future films in the Marvel movie universe.

The movie is currently shooting in Johannesburg, which looks to be the actual setting for one of the film's action sequences. Onlookers have taken to filming the action on set, and have posted the videos to their personal Instagram accounts. There is one video footage that shows a truck exploding and chaos ensuing in a busy street. Fans are speculating that this might be related to a rampaging Hulk.

Of course, Marvel movies would not be complete without a cameo by creator and writer Stan Lee. In the past, he has done appearances in previous Marvel movies playing the role of a hotdog vendor, a mental ward patient, a security guard, or just a random old man. For "Age of Ultron', Stan Lee himself confirmed that he'll be doing a cameo for the film.

Some speculate that a new superhero may be joining the team, and She-hulk is being considered. She-hulk, or Jen Walters, is a lawyer and a cousin of Bruce Banner. When she was badly injured, Bruce had no choice but to transfuse his blood into her body to save her life, but in doing so he managed to infect her with his condition. However, the effect on her is milder, so her personality is intact even after she transforms.

"Avengers: Age of Ultron' will be released in theaters on May 1, 2015.