Sonic to appear in Mario Galaxy 2? We're pretty certain they're joking. Probably.

NGamer magazine has tweeted "inside knowledge" that Sonic is to appear in Nintendo's upcoming Mario Galaxy sequel, currently scheduled for release later this year.

The guys at NGamer later tweeted this news came from a "trusted source", and that Sonic levels will take place in the "Green Hill Galaxy", after Sonic's own regular Green Hill Zone locale.

Imagine Sonic riding Yoshi... nope, we couldn't either.

The UK magazine is well known for its sense of humour, and its hard to believe Nintendo would want or need Sega's mascot in the latest Mario title. Ninty does not need the extra hype for the game - such crossovers are surely best contained within spin-off titles such as Mario & Sonic at the Olympics or true ensemble pieces such as Smash Bros. Brawl.

Still, it's an intriguing concept, and one we thought we'd report to you to enquire your feelings on the subject. Would it be a good idea? Or is it best left what it most likely is - a NGamer columnist's wet dream?

Let us know your thoughts below...