NEW YORK — Pippa Middleton told NBC News she had no idea how big her sister Kate’s 2011 marriage to Prince William would be, since she saw it as just another family wedding.

“That stopped me in my tracks, that she looked at this as, ‘Oh, my sister is getting married,’ not that, ‘Oh, I’m the maid of honor in the royal wedding,’ ” said NBC’s Matt Lauer, who conducted the interview.

The “Today” show host traveled to London last week to interview the princess’ sister, her first television interview. “Today” is airing Lauer’s report in two parts Monday and Tuesday.

Lauer said Friday he had talked to Middleton’s representatives about speaking to her during a just-completed charity bike ride in the United States. They said no, but that maybe she would talk later. A day after she got back, they called and told Lauer to fly to London.

Lauer said Middleton is shy, but very down-to-earth. “I think they are going to like her very much. I think she is going to pleasantly surprise people,” he said.