'Bubble boy' Seth Lane undergoes surgery in preparation for bone marrow transplant

The little boy with a winning smile is taking the first steps to get the bone marrow transplant needed to cure him, his family said.

Seth Lane, the 5-year-old from England who won over the Internet with his "Wear Yellow for Seth" campaign, underwent surgery Tuesday to have his gallbladder removed so he could have chemotherapy. This is all in preparation for a bone marrow transplant.

"This is new for us. He's never had any operations on his organs before," his mom, Leanne Lane, told ABC News. "He gets upset. He just says 'mummy and daddy' over and over again, but we'll be outside waiting until he's awake."

Seth's story first went viral in early March when his family posted a video of the boy holding up signs to explain his condition. Because he has no immune system, Seth has to live in an extremely clean environment and have little contact with other people.

There are a lot of things that cheer him up, including the color yellow, so he asked everyone watching the video to wear yellow on March 27 to show support for him.

Friday went well, Lane told ABC News, and it lasted into Saturday for them because of the time difference with America, where the campaign picked up a lot of attention. Even celebrities like Ashton Kutcher joined in.

"Friday was amazing," she said. "The hospital did a lot there, even the local firemen came to see him and put a ladder up to his window. He [Seth] was shell-shocked."

If Seth is ready, his mom said, the transplant will take place in about a month. His father, Nik, will be the donor. This will be his second transplant. The first, which was attempted in 2010, was unsuccessful.

His mom told ABC there's a lot riding on how the transplant goes.

"If everything goes well, he could, immunology-wise, be cured," she said.

The doctors have not given her numbers of a likelihood of success. She said she knows it's a difficult procedure but has hope for a good outcome.

"We've got a lot to get through," she said of the transplant and the process leading up to it. "It's not the easiest transplant, but at least we've got a chance."

But as she continues to point out, Seth has a sunny disposition, and his attitude makes it easier on his family.

Read more on the family's blog.

Photos used with permission.