How big is the largest star ever identified?

Question: How big is the largest star ever identified?
- Keywords:
  identified,
  size,
  space,
  star
Asked by spongebob48 to Cathal, Daphne, Darren, Jon, Katherine on 9 Mar 2012. This question was also asked by tezza.
- Darren Logan answered on 9 Mar 2012:
  
  The largest known star is called VY Canis Majoris and it is thousands of times larger than our sun.
  
  Its in the process of dying and when it does, it will form a massive supernova (sometimes called a hypernova). Some scientists even think it could collapse and form a black hole. However, it is a long way away from us, so its death will not cause us any problems.

Question: How big is the largest star ever identified?