Kiwi rugby fans - including actor Will Hall and Bachelorette Matilda Rice - will be showing their support for the men in black on their nether regions when the British and Irish Lions tour kicks off next weekend.
Jockey has released a limited edition range of "everyday supporter" undies available in every colour - so long as it's black.
Hall asked for seven pairs so he can have a fresh one for every day of the week. His passion for lucky knickers harked back to his first rugby memory when he was 6 years old, inspired by legendary All Blacks flanker Alan Whetton who always wore the same undies on game day.
"A lot of sportsmen are quite superstitious so they put the left boot on first every time or will wear the same undies every game," Hall said.
"It's cool everyday supporters get to be like AJ and wear their game day undies."
The 37-year-old has plans to "infiltrate the Lions' den" dressed up in a full red kit, only to reveal his true colours - black undies - once he's in.
And his support does not stop there. Hall is "adopting a Lion" by letting two Irishmen and a Welshman bunk with him after all the accommodation got booked out in Auckland.
"That's the things about Lions, they're the best supporters. We're not putting up with Australians or South Africans," he said.
"They are here to have a great time. It's the trip of a lifetime. Not only for the players but for the fans."
Rice was excited to receive her "everyday supporter" jockeys.
She is going to go to as many games as she can sporting the briefs. Rice said Bachelor and beau Art Green will accompany her and help out translating the rules of the game.
"It's just a fun way for everyday New Zealanders to get behind the team whether they are seen by anybody else or just yourself it's just a bit of fun.
"I'm one of those people who go and love the atmosphere but I don't really know what's going on . . . I just yell when everyone else yells. I get into it and it's really fun.
"[Green] tends to explain things to me as it goes."
Rugby-mad Hall is going to the first test and the Crusaders game but thinks the tour kick-off game in Whangarei next Saturday - when they play the New Zealand Provincial Barbarians - will be a ripper.
"All those players from the first and second division are getting to play . . . It's the game of a lifetime, they'll hold nothing back."
He recently flew down to his hometown Christchurch to see his 5-year-old nephew play his first game of rippa rugby, poignantly on the same field at Hagley Park where he had his first game as a child.
He said he's loved rugby ever since he watched the first Rugby World Cup due to the physicality of the sport.
"I just remember [Sir] John Kirwan running down the try line in 1987 and scoring that try [in the final against France] pushing out the corner flag and it shattered into a million pieces."