Jagielka and Cahill formed a dependable centre-back pairing at the heart of England's defence as Roy Hodgson's men qualified for the FIFA World Cup, though it has not deterred calls for John Terry to return to the national team.
Many believe Terry is Cahill's ideal partner in defence, given the pair play together at Chelsea in the Premier League, but Jagielka has defended a partnership that has only conceded one goal in six competitive matches.
"We spend a lot of time together and we laugh and joke," said the Everton captain, who will come up against Italy, Uruguay and Costa Rica in Group D.
"I am more than happy playing alongside Gaz. We don't spend too much time together during the season because he's in London and I am in Liverpool.
"But Gary is a Sheffield lad and I played for them so there is plenty to talk about. You want to get your partnerships on the pitch. My relationship with Gaz is good."
A more pressing issue for Jagielka, though, is his fitness that limited him to just two Premier League games since February.
The 31-year-old, however, insists he will be match fit for England's World Cup opener against Italy in Manaus on June 15.
"It was an important week last week, getting out to Portugal and getting a few more sessions underneath my belt," Jagielka said.
"I had a really good session today, so it's just getting myself ready. I don't need to be 100 per cent fit for this week. It's all about building up, getting a little bit of match practice before we go out to Miami.
"Increasing it again, and hopefully timing it perfectly for the first game in the group."
England will step up preparations for the World Cup with an international friendly against Peru at Wembley, before flying out to Miami where they are set face to face Ecuador and Honduras.
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