The Christmas Before Christmas Bus Service will be available to experience for two days from 22 November. It will run between Westfield's White City and Stratford locations, stopping off at key London locations along the way.
Those who spot the bus at a scheduled stop-off will be invited to hop on-board to experience the winter wonderland.
There will be a range of Christmas offerings available on the vehicle, and a real-life Santa will be in attendance. A celebrity conductor, who’s identity will be revealed over the coming days, is set to host the first leg of the tour.
The integrated Christmas Before Christmas campaign also includes out of home, online and social media.
Westfield plans to further celebrate the holidays with a Christmas grotto experience by DreamWorks at both of its London centres, meanwhile Westfield London is housing an indoor ice rink.
Myf Ryan, marketing director – UK & Europe at Westfield, said: "Following the success of the 2014 execution of The Christmas before Christmas, we felt it was important to continue the strategy for 2015, which clearly positions Westfield as the ultimate retail and leisure destination in the lead up to Christmas.
"With our extensive retailer and dining mix, The Christmas Before Christmas Bus and festive experiences such as the ice-rink and grotto, Westfield continues to be the ideal destination for our customers to celebrate the much anticipated lead-up to Christmas."
The shopping centre brand is also bringing its Music Cube experience back to Westfield London this month.