Singer Celine Dion penned an emotional note for her first child on his 19th birthday, reminding him that his late father Rene Angelil's guidance "continues to support and protect you".

The "My heart will go on" singer took to Instagram on Saturday to wish her eldest son, Rene-Charles Angelil, a happy 19th birthday. Dion posted a baby photo of him and a more recent one of them together, reports etonline.com.

"My dear Rene-Charles, I'm so proud of the way you're conducting yourself in life. You're a true gentleman, and I want you to know that your father's guidance continues to support and protect you… as I do," Dion wrote.

"Keep being the best of yourself… strong, passionate, and wise, as you pursue all of your dreams in life - the sky's the limit!"

"And above all, have a good time!.... Your happiness, is my happiness," she continued. "I love you so much, my dear son! Mom xx…"

Dion is also mother to 9-year-old twins, Eddy and Nelson.

January began with a heartache for the star. Dion's mother, Therese Tanguay-Dion, died on January 16 this year, after months of battling health issues.

The singer paid tribute to her late mother the following day during her show in Miami.

"We got a call from the nurses who were taking care of her so well, saying that her time was coming soon. Very soon," she described.

"So last night, I joined my brothers and sisters in Montreal and I spent the evening at her bedside. We told stories, we sang songs, we hugged each other," said the singer.