Reality television star Kim Kardashian is experiencing blast from the past, as the sales of her sex tape with R&B singer Ray J, has reportedly shot up following the announcement of her pregnancy.

Vivid Entertainment, the owner of the X-rated video, reportedly told TMZ that its sales have increased by 80 per cent after the pregnancy of Kim was made public.

Kim's sex tape with Ray J, with whom she had affair in 2003, leaked forcing the television star to sue Vivid Entertainment, the distributor of the video. However, she withdrew the suit and settled for a £3million compensation.

Kanye West made the announcement of Kim's pregnancy to an audience of over 5,000 people at the Ovation Hall at the Revel Resort in Atlantic City. "Now you having my baby," he yelled out to the crowds.

"It's true!! Kanye and I are expecting a baby. We feel so blessed and lucky and wish that in addition to both of our families, his mom and my dad could be here to celebrate this special time with us. Looking forward to great new beginnings in 2013 and to starting a family. Happy New Year!!! Xo," Kim later confirmed on her website.

Her sisters also declared the happy news.

"Keeping secrets is hard with so many family members! Especially when you are so freaking excited!!!!! LOVE is everything!!!!" said Kim's younger sister Khloe.

"Been wanting to shout from the rooftops with joy and now I can! Another angel to welcome to our family. Overwhelmed with excitement!" tweeted Kourtney Kardashian.

"Oh BABY BABY BABY!!" wrote Kim's mother Kris Jenner.

Kim was previously married to NBA player Kris Humphries of the New Jersey Nets for 72 days before filing for divorce. After the separation, she went public with her relationship with West in March.

She is still legally married to Humphries and will reportedly tie the knot with Kanye once her divorce is finalised.