There is nothing easy about overcoming an addiction and for Gwyneth Paltrow, who plays an addict in her new movie "Country Strong," it was a battle simply to comprehend why people abuse drugs and alcohol.

"Country Strong" debuts on Wednesday with Paltrow, an Oscar winner in romantic comedy "Shakespeare in Love," playing singer Kelly Canter. The actress strums the guitar and belts out tunes with ease, yet, getting her head around Kelly's drinking and drug use was among her most difficult work as an actress.

"I just couldn't understand how you could be so drunk that you could wreck people's lives and then wake up the next day and pretend everything was fine," the actress, 38, told Reuters. "I struggled with that."

To prepare, Paltrow turned to her "Iron Man" co-star Robert Downey Jr., who has recovered from addictions in his own life to stage a career comeback.

"I asked Robert, 'How does this work?'" said Paltrow. "He was really articulate about addiction and the psychology behind it. He really helped me a lot."

In the movie, country singer Canter is a star of the music industry when her drinking and drug use lands her in rehab. She is discharged before she is ready and embarks on a comeback tour, planned by her husband James (Tim McGraw).

Joining Canter on tour is her sponsor -- a budding young singer named Beau Hutton (Garrett Hedlund) -- and rising starlet Chiles Stanton (Leighton Meester). But they only complicate Canter's return to the stage.

Canter's affection for Hutton threatens to come between her and her husband, and Stanton has her mind set on overtaking the Canter and ascending to the top of country music charts.

GOING COUNTRY

Paltrow is no stranger to music. She has sung on-screen before, in her late father Bruce Paltrow's "Duets," and she is married to Coldplay frontman Chris Martin. When she sang the song "Country Strong" at last month's Country Music Association awards, she earned a standing ovation.

Yet, she said playing Canter offered new challenges. For one, a country star who sings in major arenas to tens of thousands of fans requires a booming voice.

"I could always sing a bit and I have good pitch, but my singing teacher really kicked my butt. She was like, 'There's a big voice in there, we're gonna get it out!"

Paltrow sings three tunes on the film's soundtrack, including "Coming Home," which was nominated for a Golden Globe last week. A fourth song is a duet with Tim McGraw titled "Me and Tennessee," written by Martin.

The actress also said she enjoyed the portraying Canter because she identifies with being a mature woman in an industry that favors youth.

"I loved playing a woman who was feeling her age and worried about the young twenty-something coming up and stealing her thunder," said Paltrow.

After working almost non-stop in the 1990s and early 2000s, Paltrow slowed her career's pace in recent years to focus on being a mother. She has two children with Martin, daughter Apple, 6, and son Moses, 4.

She said winning the best actress Oscar for 1998's "Shakespeare In Love," left her feeling like there was little else to accomplish as an actress, and when her father died in 2002, she was overcome with grief and didn't want to work anymore.

"My dad died, then I met my husband and then we had a kid," recalled the actress. "I was like, 'What the hell have I been doing for 10 years? My daughter really redefined my life and the way I approached everything."

After son Moses was born in 2006, "I didn't have the desire to work at all," said Paltrow.

But now she is back with roles in the smash hit "Iron Man" movies. A recent turn in TV comedy musical "Glee," introduced her to a whole new set of young fans and "Country Song" has lovers of that genre singing the praises of Paltrow.

"It's funny how much I feel country music is a part of me even though I didn't grow up surrounded by it," said Paltrow. "I love how authentic it is. I find it homey and comforting. It's about being who you are, full of soul and truth."