Listen, we all know 'Star Wars: Episode 7' will bring back Mark Hamill, Carrie Fisher and Harrison Ford. It has yet to be confirmed by Lucasfilm or Disney, but it's perhaps the worst-kept secret in Hollywood. But, if you need some additional confirmation ahead of the official 'Star Wars: Episode 7' cast announcement (rumored to be taking place on May 4), we do have word that all three of the original cast members were spotted in London this weekend as filming is set to begin.

First up, is Luke Skywalker himself, Mark Hamill. While Hamill himself kept mum on Twitter, 'Guardians of the Galaxy' star Peter Serafinowicz was a little more forthcoming on his Twitter feed:

Then, there's Carrie Fisher with a cryptic tweet about her dog being spotted in London:

Finally, Harrison Ford is perhaps the Hollywood celebrity least likely to be tweeting, but he too was spotted in London by Twitter users:

Now, it could be a massive coincidence. But, to have Luke Skywalker, Princess Leia and Han Solo all in the same city, just about two weeks before filming on a new 'Star Wars' is about to begin, that seems like a preponderance of circumstantial evidence. Oh, and then there's the fact that, DUH, of course they're in 'Star Wars: Episode 7.'

What we really want to know is who else will be joining the cast, but it looks like Lucasfilm and Disney are saving that big announcement for "Star Wars Day" next month.