New York, Sep 13 - Hollywood actress Cameron Diaz spent two hours building flower beds as part of a charity project in Boston to mark the anniversary of the 9/11 terrorist attacks.

'The Mask' star joined the Boston Celtics basketball stars Friday to build a garden and basketball court at a school in Massachusetts, reports buzzhollywood.com.

She was joined by elementary school students and other volunteers at the Young Achievers Science and Mathematics Pilot School in Mattapan.

Diaz is in Boston to film a new movie with Tom Cruise, which starts shooting next week.