Heather Mills: “We thought it would be interesting to have someone with a disability on because we wanted to prove that dancing is something anyone can do,” Greene tells PEOPLE about Paul McCartney’s estranged wife, 39, who was one of the most buzzed-about rumored cast members. “She really wants to prove to people that a disability doesn’t hamper you in any way.”

• Billy Ray Cyrus: The 45-year-old country singer, who stars with his daughter Miley Cyrus on the Disney Channel’s hit show Hanna Montana, was “terrified” about joining Dancing. “He said, ‘You don’t understand. I can hardly do the achy-breaky dance, let alone a whole routine.’ (But) I think he’s going to really apply himself,” says Greene.

• Leeza Gibbons: “I think for her turning 50, she wants to be opening new chapters – not closing them,” Greene says of the 49-year-old former Entertainment Tonight and Extra anchorwoman, who now hosts her own syndicated radio show. “I think there will be a lot of women around the country who will really associate with her and what she’s doing.”

• Joey Fatone: The former ‘N Sync member is no stranger to fancy footwork from his boy-band days. But ballroom dancing is something new for Fatone, 30. “He says he hasn’t got a clue how good he’s going to be,” says Greene. “He’s never done anything like this.”

• Laila Ali: A personal trainer and daughter of boxing legend Muhammad Ali, Laila, 29, has also entered the ring herself. “The challenge for her will be being light enough on your feet,” says Greene. “She’s had to bulk up, get muscular in order to box. So it’s going to be getting the grace.”

• Vincent Pastore: No stranger to reality shows, the former Sopranos star appeared on VH1’s Celebrity Fit Club last season. “He just turned 60 and he had a heart condition last year,” says Greene. “If Vincent can do it, anybody can do it. This is a show about real people taking it on. He embodies it more than anyone on the show.”

• Apolo Anton Ohno: At 24, the Olympic speed-skating champion is the youngest competitor to strap on his Dancing shoes. “It’s great to get someone in the middle of their career,” says Greene. “(And) it doesn’t hurt that he’s a great-looking guy.”

• Paulina Porizkova: Already a fan of the show, the 41-year-old Czech-born supermodel (named one of PEOPLE’s 50 Most Beautiful in 1990 and 1992) “just wanted to get out there and dance,” says Greene.

• Clyde Drexler: The basketball Hall of Famer follows in the footsteps of fellow Dancing athletes Emmitt Smith and Jerry Rice. “He’s a legend,” says Greene of Drexler, 44. “Along with people like Emmitt and Jerry, he’s one of those people who’s the very best at their sport.”

• Ian Ziering: “I got the sense with Ian he’s really going to throw himself into it,” says Greene about Ziering, 42, who’s best known for playing Steve Sanders on the hit show Beverly Hills 90210.

• Shandi Finnessey: The 28-year-old beauty queen, who was crowned Miss USA in 2004, brings “poise” and a “vivacious personality” to Dancing, says Greene.