In addition to her successes as an actress and her respectable reputation, Reese Witherspoon is the envy of millions of Twilighters after working alongside superstar heartthrob Robert Pattinson in not one, but two films — not to mention the fact that she's kissed him too.

When MTV News caught up with Witherspoon recently as part of "MTV First: This Means War," we asked her the first thing that comes to mind when she thinks of her "Water for Elephants" and "Vanity Fair" co-star.

"I would say [he is] the hardest-working person I've ever worked with, honestly," she said. "[He's] professional, hard-working, so appreciative, more grateful than I've ever seen anyone for where he is in life."

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Given the fact that Witherspoon has been in the business for decades and experienced every facet of being famous, we asked her to weigh in on the current fan frenzy that surrounds Pattinson wherever he goes and how it may or may not affect a person.

"I've never experienced what he has — going to premieres and there's just millions of people waiting for him to touch them," she said. "I think it must be strange, but I don't even know how to process what he deals with and Kristen [Stewart] deals with. I don't know."

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The Oscar-winning actress said Pattinson handles his fame very well, despite the sometimes-chaotic circumstances. "[He's]a really cool guy," she said.

Don't miss our exclusive sit-down with Witherspoon during Tuesday's "MTV First: Reese Witherspoon." Tune in to MTV at 7:56 p.m. ET, when the actress will premiere a previously unseen clip from her upcoming film "This Means War," followed by an in-depth interview on MTV.com.

Before "MTV First: This Means War" hits MTV on Tuesday at 7:56 p.m. ET, check out Reese's first-ever, totally adorable MTV interview, when she opened up in 1991 at the age of 14 about what drew her to Hollywood. And make sure to stick with Reese's chat when it moves to MTV.com after an exclusive "This Means War" clip premieres Tuesday on MTV!