But it hasn't all been child's play for the 44-year-old Columbus, who is leaving the helm of the movie series after transforming the first two books of J.K. Rowling's best-selling series about the world of wizards into cinematic gold.

"I was putting everything -- blood, sweat and tears -- into the movies. Physically, I couldn't do the third. I'll die of a heart attack if I do the third film," Columbus told Reuters after a screening of the new movie, which had its world premiere in London on Sunday.

"It's been such an interactive form of film making. When I'm out there with these kids, I am basically performing with them. After doing it for 300 days, I needed a break."

Columbus's efforts to bring the wizards' academy of Hogwarts School and young Harry, played by Daniel Radcliffe, to life on screen paid off handsomely in the opening instalment, "Harry Potter and the Sorcerer's Stone," which is also known as "Harry Potter and the Philosopher's Stone," in some countries.

Released last year, the first film has grossed $966 million to rank behind only "Titanic" on the all-time box office list.

The Harry Potter movies are produced and distributed by Warner Brothers, the film studio unit of the world's number one media company AOL Time Warner.

The action-packed "Chamber of Secrets" also figures to please fans of Rowling's phenomenal series, which has sold@than 175 million copies worldwide.

"I tried to make a 2-1/2 hour movie feel about 30 minutes long," Columbus said about the new adventure, which includes a flying car, an army of spiders, a monstrous snake and a top-flight, all-British ensemble boosted by the addition of dynamic Kenneth Branagh as the new Defence Against the Dark Arts professor.

SUCCESSFUL CAREER

Big box office returns are nothing new to Columbus, who broke through as a director with "Home Alone," the 1990 comedy that made a child star out of Macaulay Culkin and made more than $530 million. He followed that up with a popular sequel.

Born in Pennsylvania and raised in Ohio, the mild-mannered Columbus, who has four children aged from five to 13, has long shown a knack for appealing to mainstream audiences and working wonders with the younger set.

After graduating from New York University Film School, and while working at a comic book shop, his screenplay for "Gremlins," (1984) was optioned by Steven Spielberg, who also put his "Goonies," (1985) on the screen. Columbus's first directorial turn came with "Adventures in Babysitting" in 1987.

Some in the industry think it has come easy for Columbus and that the Potter films were certain to succeed.

The boyish grin melts away as Columbus insists it wasn't all smooth sailing. He bristles when recalling how some US critics suggested the first Potter film "made itself."

"I think there was a feeling that this was a corporate effort and the reality is that is so far from the truth," he said, adding the movies have been "the most intense and most fulfilling creative process I've experienced in film making."

After his "Home Alone" triumphs and box-office success with "Mrs. Doubtfire," Columbus took a detour from dealing with kids and tackled more grown-up themes.

He worked with Hugh Grant and Julienne Moore on "Nine Months" (1995), with Julia Roberts and Susan Sarandon on "Step Mom" (1998) and with Robin Williams in "Bicentennial Man" (1999), but did not find the experience as rewarding.

"Both 'Nine Months' and 'Step Mom' was almost a selfish thing," said Columbus, perched on a sofa in a penthouse hotel suite overlooking Central Park.

"In 'Nine Months', I wanted to celebrate my own joy at having children, and in 'Step Mom' I had to deal with the fact that my mother died of cancer and I wanted to get that on film.

"Looking back on it, I say to myself that my job is not to use film as my own version of psychotherapy. It's my job to give the audience some sense of satisfaction."

Columbus said his introspective journey ground to a halt with the futuristic "Bicentennial Man."

"By 'Bicentennial Man', I thought I was getting lazier and lazier as a film maker because I was working with such talented actors. I was just saying, 'Just bring it down a little, bring it up,' and sitting back in the chair. I felt I was just closing off as a director. I wasn't challenging myself.

"By the time I got to 'Bicentennial Man', I thought I was losing interest a little. That's the worst thing that can happen to a director."

INSPIRED BY DAUGHTER

Columbus got interested in the Harry Potter project through his daughter Eleanor, now 13, who told him the books would make great movies. He agreed and campaigned for the job.

Despite his successes, Columbus said he was full of anxiety when he started the project that came with such high expectations.

"I truly believed, the first two weeks, that I was going to get fired. 'God, they're going to fire me'. This movie had such baggage with it, the first one," he said.

"But after I made the two weeks, the kids started getting more comfortable in front of the camera and I felt that we had shot some scenes that were working and I felt comfortable.

"When Harry Potter came along it all came back, and because I was working with kids and had to work so hard to get performances, it completely revitalised me as a director. I realised this is what I need to be doing. Both films were responsible for me falling in love with film making again."

Columbus, who moved his family to London during the filming, is not making a clean break from the Potter series and does not rule out a return to direct the fourth feature.

Although he gives way to Mexican director Alfonso Cuaron for the third movie, which begins production in March and is slated to be released in 2004, Columbus will serve as producer and will be on the set daily.

"Being producer will be more of a nine-to-five job," said Columbus, who plans on paying more attention to a different set of children -- his own.

"My kids were the ones that got me into it and ironically they're the ones getting me out of it," Columbus said. "I need to be there for them.

"I promised my kids I'll have dinner with them at night."

(China Daily November 5, 2002)