The 20-year-old is relishing Quins’ Premiership title bid.
Lynagh senior also tasted domestic success on the Twickenham turf, being part of Saracens’ 1998 Tetley’s Bitter Cup final-winning team alongside fellow global superstars like Francois Pienaar and Philippe Sella.
But this weekend, it is 20-year-old wing Louis’ turn in the Twickenham spotlight as Quins chase a first Premiership crown since 2012.
And he has already played a key role, scoring one of his team’s seven tries during a stunning 43-36 extra-time victory over Bristol that booked Quins’ appointment with Exeter.
Lynagh senior won 72 caps for the Wallabies as fly-half playmaker during an 11-year Test career and scored more than 900 points, underlining his status among the sport’s all-time greats.
He was also among the Ashton Gate crowd last Saturday to watch Quins complete a record-breaking fightback from 28 points adrift.
“Dad is not a man of many words,” Lynagh said.
“We had a moment afterwards. He came down to pitch-side and we talked about how brilliant it was. I didn’t really have many words myself – I was quite emotional.
“I think I definitely will talk to him about it, because he has obviously been there (Twickenham).
“He will feed the helpful stuff, but he doesn’t like to be too hands on with me, he likes to let me find my own path. I like to think I am making my own path.
“I will always have that connection to my dad, and I am always thankful for that, not only for his help in my career, but also the opportunities I have had to meet certain people and gather information about playing rugby.
“This season, I have shown I can pull my own weight and hopefully bring my own name to the forefront. I wouldn’t mind being compared to my dad – he was a decent player.
“I have always wanted to make him proud, and hopefully that is what I have been doing since I started playing rugby at Richmond when I was four.
“It is going to be a a pretty special weekend for my family and I.”
Lynagh is among an exciting generation of young talent at Quins, linking up with the likes of fly-half Marcus Smith, fellow back-three player Tyrone Green and flanker Jack Kenningham.
And while watching footage of players like his father, David Campese and Jonah Lomu formed part of Lynagh’s rugby education, he is rapidly making a name for himself at Quins, while relishing every minute.
“I was the youngest on the team against Bristol, and it has been amazing to come in and play alongside players like Mike Brown, Danny Care, Alex (Dombrandt) and Marcus,” he added.
“Teams like this don’t come around too often, and to be part of one like this is pretty special.
“When you think about rugby and promoting audiences, that (Bristol game) is one of the ones you put on the front cover.
“It was a special game, and hopefully it can happen again on Saturday. Our brand at Harlequins is to try and entertain.”