She also appeared in the video of UK Rock Band Marillion "No One Can".
She is mainly known by her nick names i.e Terri Helene Seymour and Terri Louise Seymour. whit and black and she follows Christianity religion.
Sources said Cowell made the gesture as a 'thank you', despite suggestions it was to prevent Miss Seymour lifting the lid on their turbulent relationship.
The British beauty, who is a correspondent for US entertainment show Extra, announced her exciting news exclusively to the UK's Hello!
magazine on Monday as the couple let the cameras into their home for a glamorous photo shoot.
Her Welsh model partner adds: 'To start with, it was quite a lot to get my head around - it's such a life-changing event - but now I can't wait to be a dad and start my family with Terri.
They have also interviewed in the media that they are going to marry soon.
He must rank as the most understanding ex-boyfriend of all time.
She has just started to show and it's very exciting.'While the brunette is probably most famous for her six-year relationship with Cowell - which ended in 2008 and saw her awarded million in cash and a further .6 million to buy a home in Beverly Hills - she maintains a great friendship with the X Factor mogul.
'It has been quite hard to keep it under wraps': The 39-year-old correspondent for US entertainment show Extra chose a very clever dress to disguise her growing bump as she hit the red carpet on August 23Indeed, she tells the publication that he was thrilled when she told him she was expecting, the 54-year-old among only a handful of the couple's nearest and dearest let in on the secret prior to hitting that all-important second trimester milestone.'He's so thrilled for us,' she insists, adding: 'We were having dinner in LA and I told him and he was over the moon.
Seymour is understood to have spent the last three years and hundreds of thousands of pounds transforming the lavish property.