While all eyes are on Kimye as they plan their lavish wedding, Kim Kardashian's big sister Kourtney is said to be trying to upstage her with a grand wedding of her own.

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A source told Radar Online that Kourtney plans to finally wed her longtime boyfriend Scott Disick, of seven years, and is adamant about having a huge wedding like her sister.

"Kourtney has already seen Kim have an over-the-top wedding with Kris Humphries and now she's watching her sister turn her Kanye West date into another big affair and she's getting mad that her own wedding is going to be overshadowed. She wants her wedding to be just as spectacular as Kim's."

Kim and famous Jesus Walks rapper Kanye West are slated to tie the knot in Paris while Kourtney is said to be getting hitched in Mexico.

The source added,"For a really long time Kourtney has felt like she is living in Kim's shadow but she doesn't want her wedding to be second to Kim's THIRD trip down the aisle."

They also said that Kourtney is afraid Kim's wedding will overshadow hers because she is more famous.

"Everyone knows that Kim is the most popular sister and Kourtney really wanted her wedding to be special, so she's not planning to let Kim steal her spotlight now."

Kim and West's wedding will air on a special episode of Keeping Up With the Kardashians later this year.

A second source said their wedding will be "an over-the-top affair and there will be pre-wedding festivities leading up to the big day for their guests. It'll be like a festival!"