Although they are close and Lampard played under Redknapp early in his career at West Ham United, he now manages Chelsea's Premier League rivals Tottenham Hotspur who finished fourth and are currently heading for a place in the Champions League next season.
However, if Chelsea win on Saturday, they and not Tottenham will take England's fourth place in the competition, relegating Spurs to the Europa League instead.
Redknapp said this week he hoped Chelsea lost and Lampard joked he would not have expected him to say anything else.
"I know he said that. But if he'd said anything other than that with a straight face I wouldn't have believed him anyway," the England midfielder told reporters this week at Chelsea's training complex south of London.
"That's understandable what he's saying from his point of view."
And while he might well hurt his uncle's feelings, Lampard is totally focused on winning the final at the Allianz Arena and celebrating what he says will be the greatest night in Chelsea's 107-year history.
"For Chelsea it would be the greatest achievement for sure. We've got four players out, some of our best performers of the season. I think every step has been a huge achievement - the Barcelona games, the turnaround against Napoli. It would be Chelsea's best ever achievement if we win it now."
BANNED FOUR
Chelsea go into the game with skipper John Terry suspended along with defender Branislav Ivanovic and midfielders Ramires and Raul Meireles.
It is the latest obstacle for them to overcome in a difficult season during which manager Andre Villas-Boas was sacked in March and replaced by caretaker Roberto Di Matteo, who has helped turn the club's fortunes around.
However, Chelsea only finished sixth in the Premier League, their lowest position for a decade, and know that if they do not win on Saturday they, not Spurs, will be playing in the Europa League next season.
Lampard, who will most likely captain Chelsea in Terry's absence when he plays his 100th European club match, was not thinking about that outcome, especially as they have consistently defied the odds to get this far.
"I think we were pretty unfancied to get this far at different stages - on the way out against Napoli, then drawn against Barcelona.
NICE THOUGHT
"Not that we have surprised ourselves but when you don't see it coming the fact that you're there is even more enjoyable in a way. "We've obviously still got to go and win it but it's been a nice thought for the past couple of weeks."
There were times when even Lampard doubted Chelsea could get through, especially when he was on the bench during the last16 3-1 defeat at Napoli.
"We were struggling. It's not just because I was sitting watching it from the outside but you could see that. You wouldn't have looked too far ahead of yourself and seen this [getting to the final].
