Carrie Fisher, Harrison Ford, and Mark Hamill Confirmed for Episode VII?

In an interview with Bloomberg Business Week this week, George Lucas may have very well spilled the beans on the original cast returning for the next instalment in the Star Wars saga.



The following is taken directly from the interview:
Asked whether members of the original Star Wars cast will appear in Episode VII and if he called them before the deal closed to keep them informed, Lucas says, “We had already signed Mark and Carrie and Harrison—or we were pretty much in final stages of negotiation. So I called them to say, ‘Look, this is what’s going on.’”
Most sources are taking this as definitive proof that Carrie Fisher, Harrison Ford, and Mark Hamill will be reprising their roles for Episode VII. These same sources seem to be skipping over the next part of the interview however:
“Maybe I’m not supposed to say that. I think they want to announce that with some big whoop-de-do, but we were negotiating with them.” Then he adds: “I won’t say whether the negotiations were successful or not.”
Maybe this is just George back-pedalling after realising he's said to much. On the other hand, it might be evidence that the involvement of the original cast is still uncertain. Considering that the production team are still only in the writing stages, this seems quite likely. I'll be treating this as unconfirmed until something more concrete is announced.

[UPDATE (12/03/12): Robert Iger - CEO of Disney - has quickly stepped in, telling CNBC that none of the original cast will be confirmed as returning until the story treatment for Episode VII is complete.]