Priyanka posted an adorable collage and tweeted: "Love you @RahulGandhi."
In the collage, there are several pictures of brother and sister from their childhood. In one picture, mother Sonia Gandhi and late father Rajiv Gandhi were also seen holding the two in their hands.
The festival of 'Bhai Dooj' falls on the second day of Diwali. It marks the bond between brothers and sisters.