Rob Kardashian is back on Instagram!

On Tuesday (June 27), the 36-year-old former reality star took to social media to celebrate sister Khloe Kardashian‘s 39th birthday in his first post in over four months.

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“Happy Birthday @khloekardashian 🎈🎈🎈🎈🎈 Wishing you nothing but good health and happiness forever my darling buttercup !” Rob wrote on Instagram along with a photo of him and Khloe and a photo of Khloe with his 6-year-old daughter Dream.

“I love you so much and so thankful to have u in my life and for all that U do for Dream and I,” Rob continued. “I don’t know what I would do without you 🤞🤞🤞💙😍💘💘🍹🍹😛🏄‍♂️🍻🥵🥰🏆🧚‍♀️🦈🎾💪😈 happy birthday 🎈🎁🎂🎉”

After Rob shared the post, Khloe took to the comments to write, “My baby!!!! My favorite human being in the world. You’re my heart beat.”

Rob‘s birthday message to Khloe marks the first time he has posted on Instagram since February when shared a throwback photo in honor of their late dad Robert Kardashian‘s birthday.

It was recently revealed that Khloe is changing her 10-month-old son’s name.