The Irons defender was hugely impressed by City early on.
Claudio Ranieri's side edged out the Hammers by a 2-1 scoreline on the second week of the Premier League season. Fast forward nine months and City, with a seven-point lead at the summit of the table, look set to win a fairytale title against all odds.
Given what they have achieved since that day at Upton Park, it can be no surprise, then, that Tomkins says Leicester are the most impressive side that he has faced this season.
He is gearing up to face them once more as Slaven Bilic's men visit the King Power Stadium this afternoon, and the defender reveals that "wow" was the lasting impression that he and his team-mates got when they faced them last time around.
“You are playing Leicester at home at the start of the season, thinking, ‘We need to get maximum points here’. As it has turned out, they have gone on to achieve what they have achieved by being top of the table," he is quoted as saying by The Mirror.
“They are the best team we have played this year. The way they played against us at Upton Park was phenomenal. We turned around and thought ‘Wow!’.
“They have gone on from there – and we owe them one at their place.”
Simply put, West Ham need to win in order to have any shot at reaching the Champions League next season. Sixth in the table, Bilic and co are seven points behind fourth-placed Arsenal with only six games to go.