Taylor Swift is being sued by clothing brand Lucky 13.

The "Love Story" singer counts 13 as her favorite number and sells T-shirts with "Lucky 13" written on them through her online store, but Robert Kloetzly who owns Lucky 13 clothing - which has been trading since 1991 - feels she is stealing his business.

In a lawsuit lodged today, Robert accuses the singer of trademark infringement for unauthorized use of Lucky 13's branding, and claims they have contacted her people numerous times with no resolution. In court documents seen by website TMZ, Robert describes Taylor as a singer who likes "fast cars and dangerous men who drive them inappropriately," which is the same demographic as his company targets. It also cites the star's music video for "I Knew You Were Trouble" because it "depicts stylish, attractive, tattooed individuals in provocative situations," much like Lucky 13's branding.

Robert is seeking to get Taylor's merchandising site shut down and all of the profits she's made so far given to him, or damages paid to his company, whichever is greater.

Taylor, 24, was born on December 13, has the Twitter name TaylorSwift13 and can often be seen with the number penned on her hand.

Explaining her attraction to that particular number, she has previously said, "The significance of the number 13 on my hand ... I paint this on my hand before every show because 13 is my lucky number - for a lot of reasons. I was born on the 13th. I turned 13 on Friday the 13th. My first album went gold in 13 weeks. My first number one song had a 13-second intro. Every time I've won an award I've been seated in either the 13th seat, the 13th row, the 13th section or row M, which is the 13th letter. Basically whenever a 13 comes up in my life, it's a good thing."