R. Kelly will headline a bill of popular R&B vocalists Saturday at Conseco Fieldhouse.

On our A-to-Z list of "Double Up" tour trivia, Kelly's "R." supplies one letter and supporting act J. Holiday supplies another with his "J."

As the lone female in the lineup, Keyshia Cole provides a woman's perspective:

A is for "Ali," the 2001 Will Smith film that featured R. Kelly song "Hold On" on its soundtrack.

B is for "Bed," J. Holiday's breakthrough hit that reached No. 1 on Billboard magazine's Hip-Hop/R&B Singles chart in September and October.

C is for California, home state to Oakland native Keyshia Cole.

D is for Darkchild, nickname of Rodney Jerkins -- the prominent R&B producer who worked with both Cole and Holiday on their current albums.

E is for early exit, which Kelly made from the 2004 "Best of Both Worlds" tour co-starring rapper Jay-Z. In 2006, Jay-Z associate Tyran Smith pleaded guilty to disorderly conduct in connection with a pepper-spray attack on Kelly during the tour's visit to New York City.

F is for France, where Holiday and model Jennifer Gordon made the video for his tune "Suffocate" on the streets of Paris. Gordon also co-starred in Holiday's "Bed" video.

G is for "Give It Up to Me," the Sean Paul single that featured Cole and reached the Top 5 of Billboard's Hot 100 chart in 2006.

H is for Hammer, the "U Can't Touch This" rapper who hired Cole as a backing vocalist when she was 12.

I is for "I Won't Tell," the current Fat Joe single that features Holiday as guest vocalist.

J is for "J." -- the initial found in J. Holiday's stage name. His given name is Nahum Grymes.

K is for Kanye West, who appeared on Cole's debut single, 2004's "I Changed My Mind."

L is for Lil' Kim, the provocative female rapper who helped Cole make recent Top 10 hit "Let It Go." Missy Elliott also appeared on the track.

M is for minister, the profession of Holiday's mother, Frances.

N is for NFL Opening Kickoff 2007, where Keyshia Cole sang "The Star-Spangled Banner" before the Colts defeated the Saints at the RCA Dome.

O is for Olympics, where Kelly performed during opening ceremonies of the 2002 winter games in Salt Lake City, Utah.

P is for Public Announcement, the Chicago-based R&B group that included Kelly in its lineup until 1993.

Q is for questions surrounding Ne-Yo, the singer who performed on just two "Double Up" tour dates before dropping off the bill. "I am disappointed that I won't be able to perform for my fans," Ne-Yo said in a Nov. 20 statement. From Kelly spokesman Allan Mayer: "Ne-Yo's departure from the 'Double Up' tour was the result of a contractual issue between him and the tour promoter. R. Kelly had nothing to do with it."

R is for Robert, R. Kelly's first name.

S is for soap operas, which influenced the 22 chapters of Kelly's song/video narrative "Trapped in the Closet."

T is for "The Way It Is," Cole's reality series that airs Tuesday nights on cable network BET.

U is for undressed, the way Cole posed for the cover of December's issue of Vibe magazine.

V is for Virginia Tech, the university that inspired Kelly benefit song "Rise Up" after a student gunman killed 32 people at the school in April.

W is for Washington, D.C., hometown to 23-year-old Holiday.

X is for X-rated acts, for which Kelly is scheduled to face trial in 2008. Five years ago, the singer was indicted on multiple counts tied to a videotape that allegedly shows him having sex with an underage girl.

Y is for "Your Body's Callin'," the first track on Kelly's first solo album -- 1993's "12 Play."

Z is for "The Zoo," a track on Kelly's current album, "Double Up," in which he refers to himself as a "sexasaurus."