But while his pictures fill the cosy, welcoming shop - and his autograph tops many of the frosted delights - the cafe is very much a family affair.
Jack's oldest sister Parika ("Joob") takes on the daily baking duties. Middle sister Duangporn ("Jeeb") helps out in the kitchen and makes the drinks.
Their mother pitches in by ensuring that the pink-and-white seating area stays spotless. Sometimes Jack's father even stops in to take advantage of the cafe's free wi-fi.
"We wanted Sweet 'n Sound to have a homey, laid-back atmosphere, to be a place where everyone could come and get their minds off work," says Jeeb.
Of course, all the atmosphere in the world wouldn't matter if the desserts weren't delicious. Jeeb insists that, while some fans might at first come in hoping to catch a glimpse of Jack, they'll keep returning to get more of the high-quality, homemade sweets.
"We only use the best ingredients we can find," she says confidently.
Best sellers include their Sweet 'n Sound toast, chocolate lava cake, and white chocolate Oreo cheesecake, each Bt90 or Bt95. The shop also offers beverages including coffee and smoothies, but the favourite is iced green tea with whipped cream.
Sweet 'n Sound also sells made-to-order cakes - just call at least two days in advance. And if you do, who knows? Maybe Jack will pick up the phone and sing you a song to thank you.
Sweet 'n Sound is open daily from 11am to 9.30pm. Call (02) 710 5636 or e-mail firstname.lastname@example.org.