Gallacher Jr was again in his element during yesterday's opening round of the French Open with his world No.37 ranked father posting a five-under-par 66 in superb conditions on the National course, host venue for the 2018 Ryder Cup.
It left Gallacher well placed in third place and just two shots behind America's Kevin Stadler, who posted a seven-under 64, just two strokes off the National course record. Fellow Scots Scott Jamieson and Marc Warren were also inside the top-10 with rounds of 69.
Gallacher's son is currently on a summer school break and while younger sister Ellie is happy being at home riding her pony, Jack Gallacher did not have to be asked twice if he wanted to travel to Versailles.
In fact, he is a mini version of a pro with the TaylorMade cap, wraparound sun-glasses, golf shoes and socks, and in his back pockets there is a yardage book and tour statistic card.
The latter is normally a task for Gallacher's caddie, Damien Moore, but Jack has taken over that role.
"Jack just loves the golf and he's out here for the next five events," said Gallacher.
"I've also got my nephew, Chris, out here this week and the pair of them have been having a great time. But Jack is very serious and he will even stop people talking when I'm playing a shot.
"He's got a stats card in his pocket and he'll also carry a yardage book and when we sit down later in the hotel room he'll read out all my stats for the round. So he's really keeping Damien on his toes."
Gallacher kick-started his round to be seven under par after 14 holes, before missing a birdie putt at his 15th. However, he then bogeyed his 16th and final holes.
"I've struggled a bit the last couple of weeks, so to shoot five under is pleasing, but this is a golf course where you can never feel comfort-able," he added.
"It's one of my best rounds of the year for sure," said Stadler. "To not make a bogey out there is something I didn't think was possible when I first played it."
Warren was delighted with his 69 but unlike Gallacher was heading straight back to his hotel room after his fourth round of golf in four days. He played a practice round at Glasgow Gailes on Monday ahead of finishing first in Tuesday's 36-hole Open Championship qualifier.
"It was really solid all day except for a silly double-bogey on 11 when I wasn't quite comfortable over the ball," he said. "I'm just looking forward to going back to my bed."
Jamieson was one over playing his 17th, but he then holed a long putt from off the green for birdie and also birdied his last.
Earlier in the day, there was the bizarre sight of a topless Rafa Cabrera-Bello in the back of a courtesy car just 500 metres from the front gates of the Versailles Palace.
On closer inspection the Spaniard, who last week lost out in a play-off in Cologne, had a needle and thread in his hand and was actually sewing a sponsor's logo on the sleeve of his shirt.
"I have a new sponsor this week and it's a self-adhesive logo, but I was just sewing the corners down so it would stay on," he said, before going out to shoot a one-under 70."