The one that came from the NBA's MVP, his new teammate, Bulls point guard Derrick Rose.
"He actually texted me when I was in the Houston airport getting ready to come here," Butler said during his introductory news conference on Monday afternoon at the Berto Center. "And he said, 'Congratulations. Welcome. Maybe come by tonight and just chill out and get to know each other.' And so, that was that."
Butler, who was drafted 30th out of Marquette during the NBA draft last Thursday night, was excited about the chance to hang out with Rose.
"We went to his house and just watched the BET Awards for the most part," Butler said. "And just talked about basketball, [about] my life."
And Butler has a dramatic story about his life. He was homeless for a while after being kicked out by his mother when he was 13.
With his father out of the picture since he was a baby, Butler bounced between friends' houses before finally settling in with the family of friend Jordan Leslie and his mom, Michelle Lambert, going into his senior year of high school in Tomball, Texas.
New teammates Rose and Butler actually have a mutual friend. Randall Hampton, one of Rose's closest friends, played with Butler at Tyler (Texas) junior college.
"Randall [Hampton] was there," Butler said of the gathering at Rose's house. "He was my junior college point guard. I talked to Randall ever since I went to junior college and got to Marquette. He's been one of my best friends throughout this process. And he's always and forever one of my teammates and like a brother to me."
While Butler said he joked around with Hampton about their junior college days, it was hard for the new Bull to believe that he was holding court with Rose, a guy he's followed since Rose came into the league.
"It's crazy," Butler said. "I used to watch him on TV. Now I'm a teammate, but I try not to let that show too much to tell you the truth. He's a good dude. He's just like me for the most part and he just wants to win."
That winning attitude is clearly something the Bulls liked in Butler as well.
"It was his entire career," Bulls head coach Tom Thibodeau said of Butler. "There are certain things that we were looking for. We felt he had all the attributes that we feel are important to help a team become successful. I think he showed great progress throughout his career. [He] played in a very tough conference and their team did well."
As Butler lifted his No. 21 jersey Monday, off to the side was Lambert, the woman he calls "mom," unable to contain herself.
She'll probably be grinning, too, when he gets his communications degree in a few weeks.
"It's been a long road," she said. "As you can see, I can't stop crying. But it's amazing."
Butler's hard-scrabble story has been one of most compelling of the NBA draft. He said last week that he was glad to get it out, to discuss it, and that he "wouldn't change anything for the world."
"It was hard, but I had friends that helped me cope with that," he said. "Then, I finally met the Lamberts and they accepted me for who I was and gave me a chance at life, turned me into a better person, taught me a lot of things that I didn't know growing up. They supported me and always believed in me through the ups and through the downs."
Lambert has seen him grow from a shy teen to a confident young adult, and she simply marvels at it.
Butler's life turned one summer day when Leslie, who's three years younger, challenged him to a shooting contest, and they quickly struck up a bond. He started staying over, and it soon became a more permanent arrangement even though there already was a full house.
Lambert had three kids with her late first husband. She then married Michael Lambert, who had three from a previous marriage, and they had one child together.
That didn't stop them from taking in Butler, and pretty soon, he was calling Michelle "mom."
"I saw that my kids -- we had to share anyway because there were so many -- that they were willing to share," she said. "Jordan wanted to give up his Christmas presents to go to Jimmy. ... I knew that my kids loved him."
Nick Friedell covers the Bulls for ESPNChicago.com and ESPN 1000. Information from The Associated Press was used in this report.