The Italian, sacked at The Hawthorns in February despite having won promotion the previous season, was unveiled as part of the new backroom staff at Stamford Bridge, where he spent six successful years as a player before injury forced him to retire in 2002.
"It is obviously a challenge for me but I don't anticipate any problems," Di Matteo told the club's official website, www.chelseafc.com.
"I have got experience of being a manager, I know what it is like, and I know what it is to be a coach, so I have a bit of both and I am there to support Andre and any of the staff, to give what it takes for us to be successful. That's the ultimate challenge."
Di Matteo admitted it was an unexpected opportunity.
"His call came a bit out of the blue to be honest," said the 41-year-old, who also had an impressive stint as MK Dons manager.
"It is mostly based on the fact that he likes my football philosophy and that is why he wants me to be part of his team.
"I think he likes to play football and be positive and attacking and over the years if you have seen a game or two of the teams I coached I think we played the same way.
"I liked my teams to try and win games rather than not lose, to build, to pass.
"He is going to be in charge of it and we are going to be working the way he thinks is the right way to be successful."
Source: PA
Source: PA