The two Argentines have remained in contact since Cambiasso left.
The Argentine striker pounced in the dying stages at the King Power Stadium to snatch a 1-0 victory - three points which could yet prove instrumental in helping the table-topping Foxes win the Premier League title.
Cambiasso must be stunned over what Claudio Ranieri's Leicester have achieved so far. He successfully battled relegation with largely the same group of players under former manager Nigel Pearson last season.
However, the Inter Milan icon, who left the Premier League to join Olympiacos last summer, is happy for his ex-team-mates, according to Saturday's hero Ulloa.
“He’s happy for us because he knows the group, knows the Club and is so happy for us now. He told me this and I know he’s happy," he told City's official website.
“He said congratulations for the goal [against Norwich] and that it was a good, important three points. He’s happy for me as well.”
Ranieri's side sit two points clear at the summit with 11 matches to play, with Tottenham Hotspur their nearest challengers, while Arsenal, in third, sit five points off the pace.
They host West Bromwich Albion at the King Power tonight, where victory would see them move five points clear due to Spurs and Arsenal not playing until tomorrow.