Usain Bolt and his partner are expecting their first child together.

The eight-time Olympic gold medallist announced the news on Instagram with a picture of his girlfriend, Kasi Bennett, cradling a baby bump while wearing a flowing red dress on a beach.

Bolt, 33, wrote: “I just want to say a KING or QUEEN is about to be HERE. @kasi.b.”

Bennett, who has been in a relationship with the Jamaican former sprinter for several years, posted similar images on her own Instagram page.

She described the pregnancy in one post as “our biggest blessing”, while in another she called it “our greatest celebration”.

In a third post, she said: “Our golden child. Coming soon…”

The couple tend to keep their relationship private, but Bolt confirmed their romance in 2016.

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Our golden child ❤️ Coming soon…

A post shared by Kasi J. Bennett (@kasi.b) on

Bolt, the only sprinter to win Olympic 100m and 200m titles at three consecutive Games, retired from athletics in 2017.

He went on to pursue his desire to become a professional footballer, training with Norwegian club Stromsgodset and turning down a deal with Maltese club Valletta before joining Australian club Central Coast Mariners.

However, his A-League career lasted just eight weeks and in January 2019 he announced he was taking a step back from sport to focus on a business career.