It looks as though Pippa Middleton will be following in her sister the Duchess of Cambridge's footsteps when it comes to her pregnancy - keeping details of the journey close to her chest.

Pippa, 34, is currently pregnant with her first child. And while she has confirmed the news in a magazine column – she’s been pretty private about the other details of her pregnancy.

And now, one of Pippa’s closest relatives has revealed that there is one secret they definitely won’t be sharing regarding their new baby.

Spencer Matthews, who is younger brother to Pippa’s husband, James Matthews, revealed in an interview on This Morning that the sex of the baby is still firmly under wraps.

Hosts of the daytime show Ruth Langsford and Eamonn Holmes asked the reality star if Pippa and James knew whether they were having a boy or girl.

He then confirmed that, “They don’t [know the sex of the baby].

But it seems that even if they did, they wouldn’t be telling anyone – even close family. Spencer continued to reveal that his brother and Kate’s sister are super private, and are keeping many details of the baby to themselves.

He said, “They are extremely private and we don’t know anything.”

Spencer and his wife Vogue Williams are also expecting their first child at the moment too – meaning Pippa will soon become an aunt again for the fourth time.

Discussing the fact that his and Pippa’s kids will be similar in age, Spencer said, “It will be great for the kids to grow up together as such. We feel very blessed.”

Like her sister Kate, Pippa will likely be very private when it comes to sharing any details about her newborn baby. Although she is not a member of the royal family, she and the rest of the Middleton’s have maintained somewhat of a dignified silence in the media since Catherine married Prince William.

The only time Pippa has discussed her happy news was in a column for Waitrose Weekend magazine some weeks ago, where she revealed that she was keeping up with her exercise regime despite her pregnancy.

During her first trimester, she said, “Sport and exercise has always formed part of my daily life, from gym sessions to weekend runs, ambles or training for an event.

“When I learned the happy news that I was pregnant I realised I needed to adjust my normal 4 to 5-day-a-week routine and find a way of continuing my exercise safely throughout the three trimesters. So, the journey of pregnancy fitness began.”

Pippa is currently in her third trimester, and so fans have estimated that she is due around October time.