In a video posted Tuesday by Wahlberg on Instagram, Wahlberg showed his 9-year-old, Gracie, shooting around with Butler.
"My Gracie said she wanted to start playing basketball, so I got her a coach," Wahlberg said in the clip.
The actor then asked his daughter who her coach was, and she excitedly yelled, "Jimmy!" Butler gave the camera a thumbs up and declared himself the "best coach ever."
"Jimmy Butler coaching little Gracie? Oh, God. WNBA, here we come," Wahlberg said.
Butler and Wahlberg developed a strong friendship over many years. In a conversation between the two that was published by Interview Magazine in February, Wahlberg noted how Butler became close friends with his daughter.
"You've spent probably five years trying to win over my daughter's friendship, literally going by yourself to watch her horse-riding competitions," Wahlberg said. "Now you've become friends."
"That's my best friend in the world, I'm not gonna lie," Butler responded. "Once she trusts you, she's on your side."
Butler's off-season began after the 76ers lost to the Toronto Raptors in Game 7 of the Eastern Conference semifinals on May 12. He averaged 19.4 points, 6.0 rebounds, 5.2 assists and 1.5 steals per game in the playoffs.
According to HoopsHype, Butler earned about $19.8 million this year and is scheduled to earn the same amount next season. He has a player option that he is expected to decline, potentially making him a free agent July 1.