The 21-year-old wasn't born when his dad, Des, played for the Lions against the Rest of the World in Cardiff in 1986. But his father, who played more than 30 times at prop for Ireland, will be at Loftus Versfeld to see his son make his debut.
Des is leading a big family contingent to Pretoria where he hopes to see Luke add to his Grand Slam and Heineken Cup winners' medals this season by beating the Springboks and keeping the Test series alive.
Fitzgerald was one of five changes made by Head Coach Ian McGeechan to his team for the must win clash with the world champions. Fitzgerald joins Leinster team mate Rob Kearney in making his Test debut and will be one of seven Irishmen in the side.
It will be the biggest Irish representation in a Lions Test team since 1938, when eight played in the third Test victory over South Africa, and Fiktzgerald's inclusion in the side completes a remarkable turn around on tour for him
He missed the opening three matches of the tour because of a chest infection and fatigue after playing 30 matches in a season that netted him those titles with Ireland and Leinster.
But after arriving in South Africa he was told to take a break and was worried that he might get left behind in the race for a Test spot. It was then he asked for advice from his Dublin-based sports psychologist Enda McNulty.
"When I wasn't playing and had time to myself, things did crop into my mind but, thankfully, I got some really good advice. I've got a very good support structure in terms of family and guys I can talk to, such as Enda," said Fitzgerald.
"He's great for off-loading things that are weighing on my mind and he said to stay positive and just keep plugging away. That has really helped.
"It was difficult because you're such a long way away from home and you can feel isolated when things don't go your way.
But I've got a lot of support from players in the squad and people back at home and they help take the brunt of the pain away when things aren't going well.
"My family will come out to South Africa this week so it will be nice for them to catch up with them and be close to me in such an important moment in my career. They have always been there for me and I'm just delighted to be given the opportunity."
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