That's because his wife, Lisa, is an aspiring dressage rider with her own designs on conquering the sport she loves.
And the hours they spend at stables just outside Munich seem to be paying dividends, Lisa picking up her first title at national level over the weekend.
While the 25-year-old hones her craft in the world of prancing horses, Thomas takes a keen interest in breeding, as well as reveling in the solitude of an environment that is a stratosphere away from the pressurized spotlight he is used to.
"I come here to watch if everything's fine," he told CNN in the couple's first joint television interview.
"And for the carrots. I'm the managing director of carrots! I watch the dogs. Sometimes I help a little bit but it's her business.
"I enjoy it a lot. They make me feel comfortable, the attitude and what they look like and [the way they] live their lives. It's fun. It's easy to relax around horses."
At 25, Muller is as decorated in the world of soccer as they come.
He has a glut of domestic trophies, including three German Bundesliga titles, and claimed the European Champions League and FIFA Club World Cup crowns with Bayern Munich in 2013.
Last year in Brazil he landed the ultimate prize when Germany powered its way to a first World Cup triumph since 1990, memorably beating hosts Brazil 7-1 in the semis
before edging past Argentina in the fina
But you won't hear much talk of that landmark moment in Muller's career around the stables.
"He's interested in horses so when we are together we talk about horses and not really about football," Lisa explained.
"He knows more about horses than I know about football."
While Muller has enjoyed overwhelming success at an early stage in his career, Lisa's path is a more arduous and exhaustive one.
Though she has been riding horses since her Granddad introduced her to the sport aged four, it takes time to build a strong bond with a horse in dressage.
And though her recent victory at the Grand Prix in the Bavarian town of Kreuth shows she is clearly in tune with her horse Birkhofs Dave, Lisa says her learning curve is a lengthy one.
"You have to do eight years to learn everything but then you still don't know everything. You always keep learning," she said.
"It's not like other sports, you always train yourself, you have to get a harmony between the horse and yourself.
"It has its own mind, its own feelings. You have to become a team and that's why it takes so much time. Every horse is different so you have to feel it.
"I want to get better and better. Maybe at some point I will be very good, that's my dream. [The Olympics] would be a dream.
"I think for every sportsman it's a dream and you want to reach it but just a few people can reach it. Maybe, maybe not."
According to Lisa's coach, Götz Brinkmann, that is a distinct possibility.
Last year's qualification for the prestigious Piaff-Förderpreis -- a national series for riders aged 25 or below -- underlined her potential.
"I've never had a student that developed that fast no matter what horses they had," Brinkmann told CNN.
"She's got the will and she's got the talent and she doesn't stop. She keeps on working. And not so many riders have the ability and that makes her fortunate in a way.
"I think she'll be able to be successful on an international level for sure."
Muller is of the same opinion.
Though he is forbidden from riding himself -- to prevent sustaining an injuries that might impact on his football career -- he has taken a keen interest in the relationship between his wife and Birkhofs Dave.
Both the couple's disciplines rely on a high skill level, but also strong communication, and though the competition is fierce, Muller has high hopes for the pair.
"The potential is there," he said. "He's our best talent I think and the number one in our stable and for Lisa.
"But it's no guarantee for success because in Germany there's a lot of opponents. A lot of good riders and a lot of good other horses. Like in football.
"She has no pressure. I want that she's happy with the horses, with the work and with the competitions. But it's not easy.
"It's very tough to get up in Germany in the dressage sport. She needs time to develop her quality. We're on a good way and we need to go for it."
Muller can also see parallels in the way some horses with potential develop into thoroughbreds, whether in racing or dressage circles, while some fall by the wayside.
"There are some talents and they grow up and go to the top," he said. "And some talents don't get to the top.
"It's interesting to watch, the development of the different horses from when they come to the stable and when they leave. But he [Birkhofs Dave] stays for sure."
Muller has his own sideline at the stables too -- breeding.
"Breeding is a little bit for fun," he explained. "For sure I want to breed the best horse I can. But it's difficult and a bit of luck. But I try my best to optimize.
"My dream is one day that Lisa rides a horse that I bred. But that's a long way to go."
Though she often goes to watch Thomas play at Bayern Munich's home stadium -- the Allianz Arena -- Lisa doesn't even remotely fit the WAG stereotype.
The wives and girlfriends of high-profile footballers are often portrayed as carefully manicured, fashion-obsessed shopaholics -- an image cultivated by the tabloid newspapers.
But Lisa, who chose not to travel with Thomas to the World Cup in Brazil last year, has not one scrap of jealousy when it comes to the superstar treatment her famous husband gets.
"I don't," she said. "You have the bad sides also. Everyone comes and wants to get a photo, a selfie or an autograph. That would be too much. I can't do that like Thomas can do it.
"He's so easy going. And I want to do my horses by myself. I can groom them the best, I can ride them the best and I love them the most.
"They're my partner, my brother. I can tell them every problem. They're the most important part in my life."
This statement provoked a laugh from her husband: "I have already accepted it," he joked. "Maybe I'm number five. But it's OK."