It definitely looks like it. The Star Trek actor has been spotted on the set of Star Wars Episode VII in Abu Dhabi.
Considering Pegg is no stranger to J.J. Abrams-directed films (which includes both of the recent Star Trek films), I'm not too surprised that he may be tapped for some kind of role in the Star Wars universe, but what I'm wondering is: why all the secrecy?
Simon Pegg is a pretty well-known actor, and for them to hide him from the cast list after so many recent announcements seems strange (even strange enough to consider he's not really in the film).
IGN first reported that Pegg was seen on set, but the actor has denied any involvement, saying: "I don’t think it would be appropriate for me to be in it, to be honest. I think J.J. should cast new faces with no stunt casting."
Of course, that's just Pegg's opinion, not a definitive "yes" or "no" to being in the film. It is plausible, however, that Pegg was simply visiting the set, not shooting scenes.
Still, Abu Dhabi is a long way to go to just pop in and say hi, even if it is a chance to see Star Wars being filmed. Actually, that makes perfect sense...