Iconic composer is best known for keeping his personal life private. But on Sunday (June 1), he gave fans a rare insight into his family life as he celebrated the latest addition to his brood. The 67-year-old revealed that he had become a "grandfather again" after his daughter Mabel welcomed a "beautiful baby boy."

In the heart-warming post, Jools shared an adorable photo showing the newborn's tiny hand wrapped around his finger. He captioned the photo: "It's wonderful to be a grandfather again to a brand new beautiful baby boy. Very proud of my daughter, Mabel and extremely grateful to the midwives from @homebirth_homerton for supporting his delivery."

The joyful news saw Jool's comment section inundated with hundreds of congratulatory messages and well-wishes from fans and some of his celebrity pals. Singer Beverly Knight shared: "Huge congratulations my dear Jools!"

Sex in the City star Kim Cattrall added: "How wonderful Jools and Christabel! Congrats to all but especially to Mabel for a job well done!!!"

's praised: "Another wonderful accompaniment to the Holland family" while comedian Dawn French gushed over the adorableness of the photo and simply commented: "Oh Look."

Although the complete number of Jools grandchildren remains unknown, he has spoken out about one other grandson, Gabriel. Two years ago, while playing outdoors with the toddler he announced that he "celebrated World Topiary day with my grandson."

Jools has three children: Mabel, Rosie and George, and has largely kept his family out of the public eye. He welcomed Rosie and George during his first relationship to his former partner Mary Leahy.

After they separated, the musician then married Christabel McEwen in 2005 and they share daughter, Mabel as well as Christabel's son Frederick Lambton from a previous marriage.

In a previous interview with , Jools revealed that all of his children were raised to share his love of music, as he revealed that he was raised partially by his grandparents after his parents split and learned the importance of family values.

The musician said: "My upbringing taught me the pleasures of sociability; I grew up observing people. That's been very useful in my work because you have to get on with lots of different types when you're on the road.

"As a bandleader, I try to pass on the same family values that I grew up with: help people, hang on to your sense of humour, be tolerant and keep your judgments to yourself."