Christopher Reeve’s son Will Reeve was “nervous” about making a cameo appearance in James Gunn’s new ‘Superman’ movie. Will – who works as a correspondent for ABC News – was invited to play a small role in the new superhero film 46 years after his dad first donned the cape to play the Man of Steel and the 32-year-old reporter admitted he was more worried about delivering his one line than any of his previous TV gigs. He told TMZ.com: “I know the folks making the film, and they’ve been so kind to me and my family, and I had a free day, so we made it [happen]. “I don’t know what I’m allowed to s…