According to gonintendo, an email from SEGA arrived stating the following:
This Tuesday at the SEGA E3 Booth, SEGA will be making a major announcement for their upcoming title Sonic & All-stars Racing Transformed. There will be a large reveal, celebrity appearance and photo/video opportunities. We hope you or someone from your team can make it to cover the big news and please let us know if you have any questions.
Some speculate that the celebrity will be a fictional character, such as a man in a Mario suit announcing the Wii U version and Mario as a guest character. But I think otherwise. Mario isn’t a celebrity, he’s a fictional character. But you know who is a celebrity, has a connection to SEGA and has been mentioned in the past as being a possible racer in the first All-Stars Racing title? That’s right, Hiroshi Fujioka also known as Segata Sanshiro. If SEGA pulls a Segata reveal tomorrow, they will have won E3 without even holding a press briefing. Another possibility is Toshihiro Nagoshi, who is heading to E3. Could Nagoshi be revealing Kazuma Kiryu as a racer?