The Fake Millennium Star is similar in appearance to the real Millennium Star except that he is much larger and has a mustache and eyebrows.
During Story Mode, the Fake Millennium Star tells the player to collect the different types of Stamps to prove themselves worthy of the title "Superstar". The process goes by smoothly but, at some points, Bowser shows up in an attempt to stop them. However, the Fake Millennium Star usually just ignores him. Also, the Fake Millennium Star falls in love with Daisy and was even going to give the Beauty Stamp to her. However, the player says to the Fake Millennium Star that isn't fair and he agrees to have the player and Daisy square off. The Fake Millennium Star then wishes "good luck" to Daisy still in love with her. Near the end, the Fake Millennium Star notices the final stamp, the Mischief Stamp, is missing and it is revealed that Waluigi has taken it. The Fake Millennium Star then urges the player to get back the stamp star from Waluigi. After the player does so, the Fake Millennium Star then awards the Mischief Stamp to the player and the player is excited to be the Superstar. However, the Millennium then says to the player that he/she must beat him in one final battle. Once he/she has done so, they are waiting to be named the "Superstar". However, the Fake Millennium Star finally reveals that he is a fake and flies off into the distance never to be seen again (at least for the end of Story Mode).