LOS ANGELES — Fans of “American Idol” finalist Alexis Grace had to be careful how they dialed Tuesday night.

Grace was the 13th performer on the show, and if people had called the contestant voting number ending with 13, they would’ve been connected to a phone sex line.

Instead, producers changed the last two numbers of her call-in line to 36.

“American Idol” owns lines 01 through 12, since the show typically only has a dozen finalists.

But this year, the judges put through an extra person, causing the problem.

The problem was discovered when show host Ryan Seacrest dialed the number on his radio show, which promised a conversation with a “nasty girl” for up to $3.99 a minute.