Pop star Britney Spears has always been like a "second mom" to her sister Jamie Lynn, who is nine years younger to her.

The age gap meant there was never any rivalry between them while growing up.

"There's such a big age difference between me and my sister that I think (she) almost was like a second mom,` contactmusic.com quoted Lynn as saying.

"She's so supportive and she's so encouraging of me and she's like my biggest fan... She's always had my back,` she added.