Showbiz
The 23-year-old Twilight star is believed to be acting as the show's presenter at the London leg of the appeal.
Other names involved in the fundraiser include Jay-Z, Bono, Taylor Swift, Jennifer Aniston and Alicia Keys, says E! Online.
Event organiser George Clooney will be the main host during the bi-coastal telethon, which has been set up to raise money for victims of last week's catastrophic earthquake in Haiti.
The telethon is due to broadcast across a host of US networks, including MTV, ABC and CNN. UK viewers can watch the programme on MTV UK.
> Jay-Z, Bono 'to record Haiti charity song'
More: Robert Pattinson, Showbiz
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