Last night, on Jimmy Kimmel Live, actor Chris Pratt confirmed Sly Stallone?s appearance in the upcoming Guardians of the Galaxy sequel. While he did not reveal what character Sly is playing, Pratt did confirm the worst kept secret about the new Guardians movie. Stallone's name appears on the film's imdb page, so his cameo is not that much of a surprise to people. Critics screened the movie on Monday and the buzz has been mostly positive.