Tennis icon Anna Kournikova has posted a rare photo of her family behind the scenes on Instagram. 

The 40-year-old former tennis juggernaut now lives a quiet private life with husband Enrique Iglesias and their three children. 

That life away from the spotlight has been largely protected from her millions of fans, but she's now offered a glimpse into the family's life behind the scenes. 

Her new posts are focused on the birthday of the couple's twin children, Lucy and Nicholas, who have been celebrating their fourth birthday together. 

The couple also have 21-month-old daughter Mary. 

Anna Kournikova posts rare photos of her children. Photo / Instagram 

The adorable series of photos shows the twins playing outside and enjoying arts and crafts inside. 

A recent home video also shows the heart-melting moment all three children piled into a racing car to drive around a private tennis court together. 

Pop star Iglesias has responded to the new photos with a series of heart emojis. 

After dating several athletes — including a fling with Australia's Mark Philippoussis — Kournikova met pop star Iglesias after appearing in his video for the song Escape, and never looked back. 

She retired in 2003 after enduring some miserable years on the WTA tour, where she suffered a series of injuries. 

The greatest moment of her career came at the Australian Open in 2001 when she made a run through to the quarter-finals. 

Anna Kournikova during Anna Kournikova and the Sacramento Capitals Play the Newport Beach Breakers in the World Team Tennis Pro League. Photo / Getty Images 

Kournikova, 19 at the time, strode on to the court in a bright yellow top made especially for the year's opening grand slam by Adidas. The apparel provider was reportedly paying around $10 million of the $17m she was pulling in annually from endorsements and certainly made a splash with the eye-catching top and shorts combo. 

Enrique Iglesias and Anna Kournikova. Photo / Getty Images 

She was the most marketable figure in an era of women's tennis that couldn't have been stronger. 

It's why she remains a popular figure in tennis even now, with 1.7 million followers on Instagram. 

- by Tyson Otto