Rob Kardashian and Blac Chyna penned a heartfelt message to Kylie Jenner on her 19th birthday.

Kylie Jenner

Kylie Jenner

The reality TV star turned 19 last week and her brother Rob and his fiancée Blac - who is the mother of Kylie's boyfriend Tyga's three-year-old son King Cairo - proved they have put the family drama behind them as they sent her a card with a gushing message.

Kylie shared the card with her fans and showed the message, which read: "Kylie! I am so proud of who you are becoming and the things you are accomplishing and you are only 19!!! I LOVE YOU more than you know! Love, Rob & Chyna."

Kylie and Blac had been embroiled in long-running feud since Kylie started dating Tyga, 26, but after Rob and Blac got engaged, the family put the drama behind them.

Meanwhile, Rob and Blac are believed to be "back in love" after a recent fight.

The spat led to Rob deleting all traces of his fiancé from his social media, but the duo have reportedly already reconciled their differences.

A source said: "Rob and her have been getting into little tiffs and Blac Chyna flipped on Rob.

"He was so angry at how she spoke to him, so he deleted everything about her to hurt her.

"Rob has never cheated on her, but she is very paranoid about that from past experiences.

"[They're] back in love and have spoken through their fight."

Rob and Blac are currently expecting their first child together and are filming their own reality TV show.