Cristiano Ronaldo's Sister Katia Aveiro Pens Emotional Message After Death of His Baby Son

Katia Aveiro
Katia Aveiro
  • Oops!
    Something went wrong.
    Please try again later.

Katia Aveiro/Instagram

Cristiano Ronaldo's family is offering their unwavering support as the star athlete grieves the loss of his baby son.

Ronaldo's older sister, singer Katia Aveiro, shared a photo of Ronaldo, 37, and his girlfriend, Georgina Rodríguez, on Instagram Monday, penning an emotional message in wake of the tragic news.

"I love you and my heart is all there on this side…" the translated caption began.

RELATED: Cristiano Ronaldo and Georgina Rodriguez Detail Early Days of Their Romance in Netflix Reality Series

"May God take care of everything and strengthen your path more and more…Our little angel is already on her father's lap," the caption said referencing their father Jose Dinis Aveiro who died at 52 in 2005. "🙏 and our little girl who is here firm and strong and full of health will teach us more and more that only love matters...❤️"

Never miss a story — sign up for PEOPLE's free weekly newsletter to get the biggest news of the week delivered to your inbox every Friday.

On Monday, the soccer star shared a heartbreaking post on social media announcing that one of his and girlfriend's twins, a baby boy, had died.

RELATED: Cristiano Ronaldo Shares Sweet Family Photo from Holiday Dinner With Girlfriend and Oldest Son

"It is with our deepest sadness we have to announce that our baby boy has passed away. It is the greatest pain that any parents can feel," Ronaldo wrote. "Only the birth of our baby girl gives us the strength to live this moment with some hope and happiness."

RELATED VIDEO: Cristiano Ronaldo Announces Death of Newborn Son, Says Birth of His Twin Sister 'Gives Us Strength'

Ronaldo continued by thanking their doctors and nurses for "all their expert care and support."

For more on Cristiano Ronaldo, listen below to our daily podcast PEOPLE Every Day.

"We are all devastated at this loss and we kindly ask for privacy at this very difficult time. Our baby boy, you are our angel. We will always love you," he concluded the post, signed by him and Rodríguez.

Ronaldo is also a dad to 4-year-old twins Eva Maria and Mateo and 11-year-old son Cristiano Jr. –– their mothers have never been publicly revealed. The sports star and Rodríguez also share a 4-year-old daughter Alana Martina.

The couple announced on Instagram Oct. 28 that they were expecting twins.