British boy band One Direction was greeted by more than 3,000 screaming fans yesterday for the London premiere of its new 3D documentary "This Is Us," while music mogul and manager Simon Cowell addressed his impending fatherhood for the first time.

Cowell, 53, the owner of music and television production company Syco, which manages One Direction, is expecting a child with his friend's ex-wife, socialite Lauren Silverman.

The music magnate declined to comment publicly about the news until Tuesday, when he told BBC at the premiere's red carpet that "things are changing in my life right now, for the better."

"I'm proud to be a dad," Cowell said. "It's something I hadn't thought of before and then, now I know, I feel good about it. She's a very special girl."

Cowell also told reporters that he would be willing to let his own child become a pop star, as long as he was the manager.

Cowell joined "This Is Us" director Morgan Spurlock to share the spotlight with the boy band that has risen to worldwide fame and success since the five members formed the band on UK television singing competition "The X Factor" in 2010.

The Sony Pictures documentary, out in theaters on Aug. 30, features concert footage and the group's life backstage and on the road over the last two years.

One Direction, formed by Harry Styles, Zayn Malik, Louis Tomlinson, Liam Payne and Niall Horan, has built a devoted fan base around the world of mainly teenage girls.

In London, fans camped out for days in Leicester Square ahead of the premiere to catch a glimpse of their music idols, whose ages range from the late teens to early 20s.

"There's been a lot of grabbing today, a lot of grabbing," Payne said as he joked with reporters about the eager fans.

Malik added that he was feeling a mixture of "nerves and excitement, mainly just gratitude to our fans that have turned up and been so supportive and dedicated."

Precautions were taken to protect the band by erecting black barricades around the gardens in Leicester Square and limiting the number of attendees for the premiere to 3,000.