Olympic gold medallist Jessica Ennis-Hill is to become a mother for the first time and has been left shocked by the "very unexpected" pregnancy news.

The British heptathlon star, who won gold at the 2012 Summer Olympics in London, announced on Friday (10Jan14) that she is expecting her first child with husband Andy Hill.

She said in a statement, "I have some very unexpected but exciting news to share - Andy and I are expecting a baby. We are completely overwhelmed, with excitement and a degree of anxiety that I am sure all first time parents will relate to."

Ennis-Hill married Hill in 2013 and said at the time that she would wait until she retired from professional sport to start a family.

The surprise pregnancy means Ennis-Hill will miss out on the 2014 Commonwealth Games in Glasgow, Scotland, but the sports star says she is determined to return to professional athletics once the baby is born so she can compete in the 2016 Summer Olympics in Rio de Janeiro.

The athlete adds, "My plans for 2014 have been completely turned upside down, but having had a couple of weeks to think about things from a career point of view I am 100 per cent set on returning to full time athletics once our baby is born and go for a second gold medal at the Rio Olympics in 2016 - that challenge really excites me... I am sorry I won't be in Glasgow for the Commonwealth Games, but (I) know it will be an amazing occasion. I will be at home awaiting the arrival of a little Ennis-Hill."