Beyonce performs in Central Park during ABC's 'Good Morning America' in New York July 1, 2011.[Photo/Agencies]

Beyonce Knowles has had it all before turning 30, yet is still humbled by what she calls "the biggest opportunity of my life" -- the lead role in Clint Eastwood's remake of the film, "A Star Is Born."

The singer and burgeoning actress, whose fourth solo album "4" debuted at No. 1 on pop charts after its release in June, told Reuters she felt lucky to have landed the iconic role previously played by Barbra Streisand and Judy Garland.

Eastwood will helm the fourth remake of the story about rising singer and actress Esther Blodgett, and Beyonce fondly remembers being a young girl and watching previous versions of the movie with her mother.

"It's when I became a fan of Barbra Streisand's. And I then saw Judy Garland's version of 'A Star Is Born' and I realized every 20 to 30 years a new star is born and a new talent represents that generation and era -- so I didn't think that I would ever get the opportunity to be the star," she said.

Beyonce has won 16 Grammy Awards, is married to rapper mogul Jay-Z, has topped Forbes magazine's lists of the most powerful and influential celebrities and is one of the world's top-grossing musicians. She starred in other movies with large ensemble casts, such as the widely-praised "Dreamgirls", but she said meeting Oscar winner Eastwood still made her quiver.

"I met with Clint and I was so nervous and I know that it is the biggest opportunity of my life. I will work as hard as I can," she said. "Because I can't wait. And I am so happy that he trusts me and I am in good hands and I am so fortunate."

The film is due to begin shooting at the end of the year and, according to showbiz website Deadline Hollywood, may also co-star Leonardo DiCaprio. But for now, Beyonce is still busy managing the singing career that she has taken over from her father and longtime manager, Matthew Knowles.

The switch has the music industry watching closely. Without directly addressing her father, Beyonce said it was "difficult balancing the business and the creativity."

"Having to balance the two is really hard and really making sure that I'm still doing my job, which is to be the performer and the entertainer and not have to do everyone else's job so that mine doesn't suffer, that's been a challenge," she said.

She added: "I'm sleeping with my blackberry, I'm having dreams that I'm answering e-mails, like it's that far!"

LABOR OF LOVE

While "4," debuted at No. 1, its first week sales were her lowest to date and singles "Run the World (Girls)" and "Best Thing I Never Had" have not performed as well as other hits, from "Crazy In Love" on her first album to her third CD's "Single Ladies (Put a Ring on It)" and "Halo."

The Houston-born singer, who first experienced fame with the all-girl group "Destiny's Child," said that with "4" she wanted to make a cohesive album that was "one body of work."

"This album was a labor of love. It was not about singles," she said. "I felt like the emotion and live instruments and just soul (were) missing out of the music industry, especially the popular music that's out. I wanted to bring it back to the music I grew up listening to. It's like a mixture of the '90s and the '70s and rock-n-roll."

Beyonce heralds the video for "Run the World (Girls)" as a current favorite, but acknowledges that the black-and-white video for "Single Ladies," which showed off her swinging pelvis and rhythmic dance moves in a one-piece bodysuit, was a hard act to follow.

That video "was something that no one knew would become the phenomenon it became, thank God. And I know I am so lucky to have one of those moments in my career. It is just a blessing."

Her move to take charge of her career -- everything from her tour performances to videos -- is partly aimed at inspiring younger stars to take control of their careers, she said, citing one of her major influences, Michael Jackson.

"It just feels like no one else can tell me how I am supposed to perform, and I think it's what separates the Michaels and the Madonnas from the artists that are great but are just not quite the Michaels and the Madonnas," Beyonce said.

While some industry watchers have wondered if success has gone to her head, Beyonce seems to exhibit very little of the ego of many pop stars and said as the years progress, she will likely be living "vicariously" through other artists.

As she turns 30 years-old in September, what can she possibly achieve by, say, 60?

"I am sure at 60 I will not doing the Oh-Oh-Oh dance, that will not be cute," she laughed, referring to the 'Single Ladies' dance. "I think my priority will be my children and hopefully my grandchildren by then -- and my record label or production company or whatever else."