Walker became a cult hero with the West Ham fans after he saved a penalty from former midfielder Frank Lampard at Stamford Bridge even though the Hammers lost the game 1-0.
Walker could never have imagined that his relationship with the Hammers fans would transform onto another level following the events that unfolded in west London that evening.
Arjen Robben was brought down inside the box and despite a delay in the penalty being taken, Walker kept his nerve to keep out the spot kick from the England midfielder.
Walker still gets reminded of the penalty every time he bumps into a West Ham supporter and says it was a moment he will never forget.
Walker said: “When anyone ever asks me about the game at Chelsea I always say I don't like to speak about it! What could I possibly say!
“It was a memorable evening, albeit it for different reasons that what we are normally used to.
“We all know Frank is a fantastic player, but I didn't realise at the time how popular that penalty save was going to make me.
“After the decision had been made to award the penalty, I can still remember the delay that took place as I think Tomas Repka was arguing with a few people!
“I didn't think that would affect Frank as he is normally so composed in those situations, but I managed to get a block on the ball as he attempted to hit the ball straight down the middle.
“Ludek Miklosko was my goalkeeping coach at the time and although we had information on the opposition, there was not the footage available like there is now to study the penalty takers. I just stayed up as long as I could and managed to save it.
“The funny thing is that whenever I speak to West Ham fans about the game they never ever mention the result! I haven't bought a drink in Essex for the last ten-years.”
Walker is planning to make his first appearance at London Stadium for the game this evening and knows more than most the amazing atmosphere that can be generated under the lights.
The 43-year-old would love to see the Hammers make amends for the League Cup defeat back in 2004 and record a famous win over their London rivals at London Stadium.
“I know the new Stadium can help take the Club onto the next level. I have played under the lights and know the amazing support that the West Ham fans can provide for the team.
“This is a massive game and it would be nice to see the Club have a good cup run.
“I cannot believe I was part of the team that last reached a major final and it is long overdue.
“I can remember what the FA Cup run did for everyone at the Club back in 2006 and it brings everyone together.”