McKayla Maroney shows off a sweet youthful smile on the set of "How I Met Your Mother." Does that mean she was impressed with the hit comedy series, or was she charmed by Neil Patrick Harris playing Barney Stinson?

Sixteen-year-old Olympic gymnast McKayla Maroney became instantly famous after her 'not impressed' expression went viral online. Thanks to a Tumblr page dedicated to her silver-winning moment, Maroney has been known as the girl who is hard to please. But things are changing these days, Maroney has been smiling in her latest photos.

In the photo below (posted by Neil Patrick Harris on Twitter), the young gymnast is looking very 'impressed' while showing off her silver medal alongside Harris.

In shouting out about the photo @ActuallyNPH tweeted: "Guess who visited HIMYM just now? Olympic Gold Medalist @McKaylaMaroney! Here I am pointing at her: pic.twitter.com/UnSipt7R"

How I Met Your Mother Season 8: McKayla Maroney ‘Impressed’ with Barney Stinson on the Set? Photo: Neil Patrick Harris/Twitter

Maroney retweeted the photo and shouted out: "It was so amazing to meet you @ActuallyNPH!! You're the best!!"

Maroney was also photographed with the series' Lily Eriksen, played by Alyson Hannigan. It is not clear whether Maroney has filmed a cameo appearance in one of the Season 8 episodes.

How I Met Your Mother Season 8 Spoilers

E! Online recently reported what fans could expect at the premiere episode of the upcoming eighth season of the CBS comedy.

"The good news is that in the season premiere, we are still in the flash forward to their wedding day, and Robin and Barney are totally in the same place emotionally when it comes to marrying each other," according to "Watch with Kristin."

"The bad news? That place is: "I can't go through with this!" And while Ted is trying to talk Robin down, we learn that something important happened before the wedding that could really muck up the whole Barney and Robin relationship."

Any guess on what or who could be involved in the aforementioned "something important?"

How I Met Your Mother will return for what could be its final season on CBS this fall.

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