49ers fever is heating up ahead of Sunday's game, and the spirit is leading to big business for the Cukui boutique in San Jose's Japantown thanks to a shirt design inspired by the team's star quarterback.

Orly Locquiao, the artist and boutique owner who designed a Colin Kaepernick inspired t-shirt, told KTVU the shop can't keep them on the shelves.

More of the coveted t-shirts arrived Wednesday evening in the stockroom of Cukui. The design of the shirts is based on the tattoos sported by Kaepernick.

They say "Against All Odds" across the chest. The back features an image of St. Michael battling the devil on the back interwoven with Kaepernick's name and jersey number.

"We didn't realize how big of an impact it would bem so we decided to do some more," said Locquiao.

Like the 49ers quarterback, the t-shirt has become an overnight sensation. The demand started with Loquaio's family, who waited in line to buy their own.

Michelle Locquiao says she sold 300 t-shirts Wednesday. Fans are calling the store to pre-order more.

"We did sell out today," said Michelle Locquiao. "This is our very last t-shirt and everyone wanted to buy it, but I said 'You have to come back on Friday.'"

The success has taken the small business owners off-guard, as has the Locquiao family's newfound friendship and business relationship with the sports star everyone is talking about.

"It's pretty cool to see someone come out of nowhere and make something out of himself," said Joey Armstrong, tattoo artist at San Francisco's Seventh Sun Tattoo.

At Seventh Sun, 49ers fever is starting to leave an indelible mark as artists brace for a possible run on Kaepernick-inspired tattoos.

"I did a Super Bowl trophy [tattoo], and it had all the different years the 49ers had won it," said Armstrong. "If they win this year, he's going to have to add another year."

Orly Locquiao told KTVU that sales in his store were up 200 percent over the past month thanks to lucky number 7. He also said he was working with Kaepernick on a new tattoo design to be inked after the end of the football season.