Brett's further contribution to film scores includes writing collaborations with Kamen on features such as The Event Horizon, What Dreams May Come, The Iron Giant, Frequency, X-Men, and the mini series, Band of Brothers produced by Steven Spielberg.

[citation needed] In 1999 Brett helped produce the concert that saw Metallica pair up with The San Francisco Symphony Orchestra as assistant Musical Director.

[clarification needed] In 2002 Brett went on to plan and execute, again as assistant Musical Director and in close partnership with the BBC, Party at the Palace (part of the Queen's Golden Jubilee Celebrations).

[citation needed] To mark the global relaunch of Disney Stores, Brett was asked to write music designed to thrill both children and parents alike.

Working with the BBC and Gary Barlow in 2012, Brett composed and conducted the Diamond Jubilee of Elizabeth II, celebrating the 60-year reign of the Queen alongside Paul McCartney, Annie Lennox and Stevie Wonder.