Singer Ashlee Simpson is "really excited" about her sister's wedding.

The 29-year-old will be bridesmaid when Jessica Simpson ties the knot with Eric Johnson next month and can't wait to be by the `Dukes of Hazzard` star's side when she walks down the aisle, reports contactmusic.com.

"I don't know when it is. I'm really excited about it,` she said.

Ashlee, who is engaged to Evan Ross and has five-year-old son Bronx with ex-husband Pete Wentz, thinks her sister has "amazing taste" and is overjoyed by the dress she will wear on the big day.

She added: "My dress is really beautiful! It's really, really stunning.''