Gwyneth Paltrow "lost her appetite" through nerves over singing live at the Country Music Association awards (CMAs) tonight (10.11.10).
The 'Country Strong' actress - who plays a down-on-her-luck alcoholic country singer in the film - is set to perform the movie's title track at the awards show, and said she was so nervous she didn't sleep well last week, but is now prepared for her performance.
She told Usatoday.com: "I actually feel better this week about singing the song on the awards show.
"I was really bad last week; I lost my appetite and I couldn't sleep. I feel prepared this week. If I can keep my nerves under control I can survive it."
Gwyneth, 38 - who is married to Coldplay singer Chris Martin - will take to the stage alongside Vince Gill at the awards, which will see the biggest stars of country music watching her.
In preparation for the film, Gwyneth - who is famed for her svelte figure - had to eat lots of fatty treats such as fried chicken, in order to bulk out for the role.
Her personal trainer, Tracy Anderson, told People.com: "She's never been a dieter, she loves to eat. They wanted her to eat a lot of fried chicken. It was frustrating for me, but they wanted her to gain."
Tracy added, however, she was never worried about Gwyneth losing the weight again, and that as soon as filming had finished she went back to her usual eating and exercise routine, and quickly dropped the weight again.
She added: "When I trained her for the first 'Iron Man' movie, I took 30 pounds off her. And she's been consistent ever since."
'Country Strong' is in cinemas from January next year.