Catherine Middleton looked lovely on her wedding day, of course -- all smiles, long train and romantic hair. But is it possible her younger sister was really the one who stole the show?

Pippa Middleton, who served as maid of honour at the royal wedding, looked quite breathtaking in a cream Alexander McQueen creation. And the fact that she was surrounded by cherubic children in matching ivory gowns only made her look more angelic as she strode down the aisle of Westminster Abbey.

Pippa was certainly the talk of the Twitterverse Friday morning, with users all a-twitter over her dress.

Some debated whether it was inappropriate for a bridesmaid to wear ivory or whether it worked with the overall colour scheme. Others, it seems, simply wanted to discuss Pippa's figure.

Unlike her older sister's requisitely-modest, long-sleeved, full skirted gown, Pippa's slim number featured a rather daring, plunging cowl neckline, playfully short capped sleeves and a silhouette that was distinctly figure-enhancing.

If the front of the dress didn't capture the eye, the back surely did, with its long row of 58 silk-covered buttons pointing the way to where many an eye chose to rest: on Pippa's bottom.

"Highlight of the day was clearly #pippa middleton's bum. There I've said it. #royalwedding" opined Dave Curtin, who tweets under the handle @realdavecurtin.

"This wedding has mainly been about Pippa Middleton's amazing arse, hasn't it?" tweeted Times columnist Caitlin Moran, whose quip quickly rose to become a Top Tweet.

Prince Williams' younger brother Harry seemed to also notice Pippa – and many noticed Prince Harry noticing. Harry was spotted several times by Twitter users, who caught him glancing several times at his new sister-in-law's little sis.

"Prince Harry & Pippa Middleton - anyone else thinking what I'm thinking? #royalwedding" wondered CNN's Piers Morgan.

Retired cricket star Michael Vaughan earned himself a Top Tweet when he cracked: "Lets all pray for Harry.. pray that he gets lucky tonight with Pippa. #goonharry"

CTV's own gossip lover Elaine "Lainey" Lui tweeted "Um... Pippa and Harry need to slow dance tonight and make [stuff] happen. Look at them on the balcony!"

Kate herself was likely not following the chatter on Twitter today. So one wonders what she will think of all the attention lavished on her sister on what's supposed to be her big day.

Twitter user @Jon Smalldon seemed bemused at the idea too.

"The Middleton mother must be so proud," he tweeted, "Kate becomes Princess Catherine and Pippa's bottom trends on twitter."