Reese Witherspoon has sent fan mail to Naomi Watts telling her she was struck dumb after watching her performance in The Impossible, a film about the 2004 Indian Ocean tsunami.
Entertainment Weekly published the letter, in which the Oscar-winning actress said The Impossible rendered her unable to speak for 24 hours.
"It was more than a movie. It was a mediation on life and family and humanity. It was fortifying. But the life-breath of the film is you."
Watts has been nominated for a Golden Globe and a SAG award for her role in The Impossible, about a family holidaying in Thailand who are caught up in the tsunami.
She plays a doctor, Maria Bennett, who with her husband Henry (played by Ewan McGregor) fight for their own survival and that of their three sons, swept away, dragged underwater and, tangled in debris by the tsunami that ultimately killed more than 230,000 people in 14 countries.
Vanity Fair quoted Watts as saying that she initially had reservations about the film:
"I thought, Wow, it's something that affected so many lives, and took so many lives,'' she said.
"The idea of doing a disaster movie that would be so wrong if they made it spectacular in any way ... But once I read four or five pages of the script, I knew I had to do it. Because it felt completely rooted in truth, and it was."
A reviewer in Rolling Stone calls Watts' performance "an acting triumph," telling filmgoers to "prepare to be shaken" by the depiction of a true story.
In her letter, Witherspoon said Watts' performance in the film ranked her among some greats of American acting.
Not since I saw Meryl Streep's performance in Sophie's Choice have I been so moved by an actress's performance. It also reminded me of Sally Field's Norma Rae as well. Such strength and absolute vulnerability in the same performance.''
Witherspoon, whose portrayal of June Carter in Walk the Line earned her the Oscar for Best Actress in 2006, went on to wish Watts awards success.
"If I have anything to do with it (and I will literally tap dance on Sunset Boulevard for you!), you will be holding every beautiful statue that exists by the end of February."