He arrives at Children's Medical Center Dallas wearing a silly felt hat, like Santa's, except this one is blue and sports a Mavericks logo.
He slipped into the hospital, as he's done for a decade now, with a jolly disposition and enough Christmas presents to fill a large rolling bin.
He will introduce himself as a kind-of relative to many of the 19 all-too-young patients he will visit, individually, during the next four hours _ a famous, yet endearingly unpretentious one every kid wishes they could have.
Uncle Dirk.
His fiercely competitive alter ego, Dirk Nowitzki, has for 19 NBA seasons thrilled fans with his basketball feats, but that pales in importance to the smiles, giggles and wonderment Uncle Dirk will induce on this day.
"How many years did it take you to grow that, that, that tall?" 7-year-old patient Legecy Allen asks. "You can barely fit through that door!"
"I know," says grinning Uncle Dirk. "I think I was like 7-feet when I was 18, so it took me about 18 years. Now I'm almost 40."
He's actually just 38, not that it matters to these kids. Nor do they care that because of a strained Achilles, he has played in only five of the Mavericks' 28 games this season.
During these precious hours in Children's, the Mavericks' 7-21 record and his personal struggles also are unimportant to Nowitzki. Here, for the kids' sake, he must be Uncle Dirk.
"These definitely are some tough times," he said. "But this definitely takes your mind off of basketball for a while."
Nowitzki fans generally know about his philanthropy and particular soft spot for kids, but the public never has had a window into Uncle Dirk's hospital visits because he wouldn't allow it, no offense intended.
No press releases. No photo ops. Not a solitary tweet.
After lengthy deliberation, he's consented to The News shadowing him during this visit, but with a request: That the story be about the "courageous" kids, their "amazing" families and the "incredible" doctors and nurses.
On this day, Uncle Dirk will visit kids with brain tumors; kids awaiting bone-marrow transplants to fight leukemia and sickle cell anemia; an infant heart transplant patient; and a 6-month-old, 8-month-old and 2-year-old who have never lived a day outside a hospital.
"It's rough sometimes," he said. "It's frustrating at times. You're speechless at times.
"But this is always my favorite appearance of the year. It means a lot to the kids and the parents and, obviously, to me."
