Rob Kardashian has opened up about why he really ditched his invite to attend Kim Kardashian and Kanye West's wedding, and it's not because he didn't want to stick to the colour theme.

In fact it was mostly to do with his self confidence at the time, as he became increasingly aware of his weight during prep for his sister's big day.

"I was doing suit fittings in Paris right before the wedding and I just wasn't comfortable. I'm 6'1" and at my most I probably weighed 300lbs," Rob told People.

"There were cameras at the airport on our trip there and I was very unhappy with the person I saw in all the pictures.

"I'm upset I missed my sister's wedding but it was a personal decision."

Fingers crossed Kim doesn't decide to do the same for Rob, who is set to marry fiancée Blac Chyna in the near future.