The Ivory Coast international is looking forward to facing former Chelsea team-mate Gallas and compatriot Kolo Toure.
"Hopefully I will score on Sunday," he told Sky Sports. "I will be against my mates but they also know it will not be easy for them.
"William knows he is coming to the cauldron of Stamford Bridge, like with Ashley Cole [at Arsenal], he will be booed. But they are top players and I will need help from the crowd to unsettle William."