Mumbai, Aug. 12 -- Wishing his "appa", Sara Ali Khan, on her birthday, Ibrahim penned a heartfelt message on Instagram.

"Happiest birthday to my appa jaan (heart emojis). Love you the most and thank you for being the best sister ever," he wrote.

Ibrahim also shared an adorable picture with Sara, posing together against the warm glow of a bonfire.

Earlier in the day, Kareena posted the picture on her Instagram Stories, featuring herself, her husband Saif Ali Khan, his son Ibrahim Ali Khan and Sara.

Alongside the image, Kareena wrote a playful birthday message: "Happy birthday, Sara darling ...to more pumpkin sabzi and now yoghurts. May your plate always be full..."

Sara is the daughter of Saif Ali Khan and his first wife, Amrita Singh...