Alice Coltrane
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Alice Coltrane was one of Donna Noble's friends in a parallel world. Though no one else at their Christmas gathering could see the Time Beetle, Alice stared at Donna Noble's back.
She was one of the first people to tell Donna, "There's something on your back." Even as the Webstar attacked London from above, Alice's remained transfixed on Donna's back.
At some point beforehand, she claimed to have seen the ghost of Earl Mountbatten at the Boat Show. (TV: Turn Left)