"Every situation Regina and I sing about, we've been through," Leigh said.
Leigh and Nicks, who will perform tonight at 7 at Apollo Civic Theatre in Martinsburg, W.Va., take turns singing lead.
Leigh, 29, said their harmonies come naturally, and they haven't needed much practice.
"We almost can read each other's minds; we're right there together," Leigh said.
As one of the few women duos in country music, it's inevitable that someone would refer to Leigh and Nicks as the female Brooks & Dunn - the powerhouse partnership of Kix Brooks and Ronnie Dunn that has been scooping up country vocal duo awards for years.
Leigh - whose husband, Tony King, plays guitar and sings with Brooks & Dunn - said she finds the comparison a bit intimidating.
"It's a little scary going up against them," she said.
Despite their conflicting tour schedules, Leigh said she and King have a strong marriage because they both understand the demanding lifestyle of the music business. She got to see him perform last week in Nashville, when Brooks & Dunn did a concert with her former boss, Reba McEntire.
Leigh and Nicks have a special place in their hearts for McEntire, who inspired them to break out on their own.
Leigh sang backup for the country superstar, and Nicks was McEntire's personal assistant.
"She's so proud of us for stepping out and taking a chance in the business," Leigh said.
Nicks and Leigh had been friends for years. They once lived in the same apartment complex, and Nicks took care of Leigh's Maltese, Jasmine, when she went on the road.
Neither was a newcomer. Leigh, a North Carolina native, made her first country record at age 13. She sang with the country trio Dave & Sugar from 1988 to 1993 before joining McEntire on the road.
The Texas-born Nicks sang in church choirs, youth groups and nightclubs before she moved to Nashville in 1990 and started working for McEntire's Starstruck Entertainment. Nicks, 32, now lives in Mississippi with her husband, U.S. Air Force Captain Jeff Nicks, and her 10-year-old son, Wesley.
One question was what to name the duo. Suggestions included R&R and R Squared, but the two liked the way Regina Regina sounded, Leigh said.
Because having the same first name causes some confusion, they refer to Leigh as "the blonde" and Nicks as "the brunette."
Their five band members call Regina Nicks "R.N.," and they refer to Regina Leigh as "Leigh," pronouced "Lee" - which is fine until their road manager, whose name is Lee, shows up.
By any name, Regina Regina is starting to roll. The two have given about 50 concerts since May, and they bring a lot of energy to their shows, Leigh said.
"We love what we do, and we have fun doing it," she said.
Leigh's mother runs their fan club, and the list of admirers continues to grow.
Regina Regina hasn't topped the charts yet, but Leigh said she already feels successful.
"We're convinced that there is something bigger and better for us. We're waiting our turn," she said.When:
tonight at 7
Where: Apollo Civic Theatre, 128 E. Martin St., Martinsburg, W.Va.
Tickets: $15 and $20, also available at the door
For information: Call JDA Productions Inc. at 301-714-0134 or 1-888-JDA-SHOW