TINSELTOWN SPYWITNESS.

THE 'LINE' FORMS HERE: Reese Witherspoon looked cool, calm and collected with hubby Ryan Phillippe during the ``Walk the Line'' premiere at AFI Fest 2005 on Thursday.

That definitely wasn't her mood when she and Joaquin Phoenix took voice lessons to perfect their roles as June Carter and Johnny Cash.

``The first recording session was awful, terrifying,'' said Witherspoon, who also learned how to play the Autoharp. ``I screamed. I threw up. I never stopped being nervous. My ears were sweating. My knees were sweating.''

Phoenix spent every moment on the set having an affair with a guitar.

``I started holding the guitar no matter what I was doing,'' he explained. ``I always had a guitar.''

The movie about the country music icons is getting rave reviews. But the two don't plan to take their act on the road.

``The first time I pulled out my guitar after shooting the film,'' Phoenix said, ``I played like one chord and I was like, 'I'll put that back.' ''

BIG BREAKTHROUGHS: What young British actresses could follow in the successful footsteps of Keira Knightley and Rachel Weisz?

The UK Film Council bet on Mary Nighy and Emily Blunt at a ``Breakthrough Brits'' champagne luncheon at the Four Seasons Hotel on Tuesday that honored emerging British women throughout the film biz.

Nighy's parents hadn't always expected their daughter to receive this type of accolade in Hollywood.

``My mother wanted me to be a physicist, and my father wanted me to be the new Hemingway,'' said Nighy, 21, who plays Princess de Lambelle in the upcoming ``Marie-Antoinette'' directed by Sofia Coppola. ``They wouldn't let me start acting until I was 17, but I'm sure they'll be more encouraged now that I'm a certified Breakthrough Brit.'' The daughter of actor Bill Nighy joked that the award presented by Oscar-nominated British actress Brenda Blethyn might even give her career a lively boost.

``I wear corsets and wind up dead in the two historical dramas I've made so far,'' said Nighy, referring to ``Marie-Antoinette'' and her role as a courtesan in ``The Fine Art of Love: Mine Ha-Ha.'' ``Maybe now I can play a character from the 21st century and make it to the end of the movie.''

Of course, there's no guarantee of success even for a Breakthrough Brit. ``Americans think British movies are in a foreign language and often don't understand what our culture is all about,'' said Mia Bays, an honoree for her work in film marketing and production. ``Fortunately some Americans are still a bit impressed by our accents.''

Not all of the Breakthrough Brits were able to make it to the Four Seasons. Emily Blunt was stuck in New York, where she's shooting ``The Devil Wears Prada'' with Meryl Streep. Watch for her accent.

TIMING IS EVERYTHING: Nicole Richie displayed Cinderella-like timing in Hollywood on Thursday night. She politely posed with a uniformed Marine sergeant before abruptly leaving the Motorola Toys for Tots party at the American Legion at precisely 11 p.m. Exactly five minutes later, those hot-stepping sisters, Paris and Nicky Hilton, arrived. Richie and Paris are obviously still feuding, though Richie did speak to Hilton's parents earlier in the evening, Fortunately, their ongoing spat didn't prevent other celebrities - including Catherine Bell, Shannon Elizabeth, Amber Tamblyn, Molly Sims, Mena Suvari and John Stamos - from contributing unwrapped toys to the program that distributes gifts to needy children at Christmas.

``I brought an iZ (the musical toy - it looks like a friendly alien - that connects to your iPod), which is definitely the hot gift this year,'' said Stamos, explaining that the interactive music machine can hoot, rap and burp. ``But I'm also here because I use a cell phone all the time on 'Jake in Progress' and want to stay tight with Motorola.''

The Hilton sisters, who stayed to see Salt-N-Pepa perform, weren't bearing any visible gifts. Maybe they became Barbie dolls at midnight.

We Saw U

Whitney Houston and Bobby Brown intimately snuggling in the bar at the Four Seasons Hotel.

Paris Hilton giving a good night kiss to 'N Sync-er J.C. Chasez at Blender magazine's ``Rock and Roll Hollywood'' party at a private mansion in the Hollywood Hills.

Mike Tyson and Serena Williams flexing their muscles and comparing their biceps at the Blender bash.

Lindsay Lohan sneaking backstage at the Vogue CFDA fashion show to check out an Orchid Collection dress designed by Derek Lam.

Angelina Jolie in a Belstaff aviator jacket at her latest flying lesson.

CAPTION(S):

5 photos

Photo:

(1) HILTON: What's a mere five minutes ...

(2) RICHIE: ... between (formerly close) friends?

Jeff Vespa/WireImage.com

(3) PHOENIX and WITHERSPOON: Walking 'The Line'

Getty Images

(4) JOLIE: No fear of flying

LDP Images

(5) NIGHY and BLETHYN: Breakthrough Brit and her inspiration

Frazer Harrison/Getty Images