It looks the members of the "Wolfpack" had a little catfight. Bradley Cooper is said to have irked his "Hangover 3" co-star Zach Galifianakis with his diva-ish behaviour so Zach decided not to attend their press conference in Brazil.

The official word was that Zach did not attend the conference because he was afraid of heights. However, there was apparently another reason why.

The media conference was held at the Morro da Urca, which is the first hill up on the way to the famed Sugarloaf Mountain in Rio de Janeiro, on Wednesday. The only way to get there was to ride a cable car, which apparently became a problem for Zach.

"Zach is afraid of heights, and called into the press conference to let participants know, and made a few jokes," a rep for Warner Bros told the NY Post.

But according to local publication Glamurama.com, Bradley was to blame for his co-star's absence.

The media conference was scheduled in the morning, but was cancelled because the cast members couldn't agree on the timing for the event. Zach also allegedly acted like a diva, and he had fought with Zach while they were staying at the Fasano hotel before the conference.

In the end, Zach opted not to go, while Bradley made it to the event, although he was late. The paper also noted that Bradley ignored his fans who begged for his photo and autograph, and was not receptive to questions from the reporters.

When asked what was his bachelor party like before he got married to actress Jennifer Esposito, whom he married in 2006 and divorced in 2007, he just answered, "I never had a bachelor party."

"Hangover 3" opened to negative reviews last week, with some critics saying that it is even worse than the second film. The good news is that it is doing quite well in the box office, already earning over $88m in just a week.

The film brings back the rest of the cast from the first and second film, including Ed Helms, Ken Jeong, Justin Bartha, and Heather Graham.