She was a friend of Sabalom Glitz, who told her about the Doctor, his ability to regenerate, and his TARDIS. Using this knowledge she came up with a plan to trick Ace into thinking she was the Doctor and using her to rob the Bank of Ricosta. She drugged the Seventh Doctor with a Time Lord neurotoxin, stole his clothes and took recordings of his voice. She put on his clothes, wore a wig, used a hologram face-effect, and the voice recordings to fool Ace into thinking she was the Doctor, before Gloria had herself shot with a fake laser. Ace then thought she saw the Doctor regenerate into a new incarnation.
Unfortunately for Gloria's plans, Ace was imprisoned by Ricostan officials. However, Melanie Bush was also on Ricosta at the time and Gloria approached her at Lefty Lonnigan's funeral. She thought she tricked Mel into believing she was the Eighth Doctor, but Mel wasn't fooled. She eventually discovered that Mel, when working with Sabalom Glitz, had emptied her accounts completely, leaving her with no money. She vowed revenge on Mel. (AUDIO: A Life of Crime)