Casey Affleck has a message for his new sister-in-law.

Over the weekend, the Academy Award-winning actor posted what appeared to be a throwback photo on his verified Instagram account of himself with his older brother Ben Affleck and Jennifer Lopez, writing in the caption "Good things are worth waiting for."

"Here is to twists and turns, new beginnings, and finding new reservoirs of old love," the caption went on to read. "Welcome to the family. Get ready for some real dysfunction! Kidding. I am kidding."

"Jen, you are a gem," he concluded. "We love you so much!!!"

The elder Affleck and Lopez eloped in Las Vegas in June, making it to the altar 19 years after ending their first engagement.

This weekend they reportedly held a wedding ceremony at Ben Affleck's sprawling estate in Riceboro, Georgia.

On the day of the wedding, Casey Affleck was filmed in Los Angeles in a video that was posted on TMZ.

It's the second marriage for Ben Affleck, who shares three children with his ex-wife, actress Jennifer Garner, and the fourth for Lopez who has twins with ex-husband singer/actor Marc Anthony.