WINDSOR, U.K. -- The royal groom and his best man stepped out of Windsor Castle Friday afternoon to greet well-wishers from around the world. Many of the people cheering were Americans who are in Windsor to watch an American actress marry into the British royal family.

Ann Webb said she came here not only for close-ups, but also to witness history.

"It's just neat to see how the monarchy's changed," Webb said. "The evolution of the monarchy, and how here we are today marrying an American, a divorced American, biracial woman it's just fun to see."

She said she thinks Meghan Markle is helping to break tradition.

Markle announced earlier Friday, before having tea with her mother and the queen, that her future father-in-law, Prince Charles, will now walk her down the aisle. But only partway, said CBS contributor Tina Brown, who wrote a biography on Princess Diana.

"She's saying I'm going to walk down the aisle, just the beginning alone," Brown said. "I make my entrance alone. That is a great statement really. It says, 'I'm not being given to anyone. I'm actually giving myself,' and it's a lovely gesture, I think. It maybe even become the next tradition for brides."

Brown says there's "no precedent" for a bride to enter on her own. "But this has been a wedding all without precedent," Brown said.

In other firsts for a royal wedding, a gospel choir will perform for the service at St. George's Chapel. And while the head of the Church of England will preside over the vows, an American bishop will deliver the address.

