The famous friends reunited at the National Board of Review Annual Awards Gala in New York City on Wednesday, where Cooper presented the "Once Upon a Time in Hollywood" actor with the best supporting actor award, according to People.
As Pitt took the stage, he had nothing but kind words for the "A Star is Born" actor and credited him as being the reason he became sober.
"Bradley just put his daughter to bed and rushed over here to do this," Pitt told the crowd, per People. "He's a sweetheart. I got sober because of this guy and every day has been happier ever since."
In 2017, Pitt gave a very open interview to GQ magazine, in which he opened up about his past substance abuse issues and said he was living a clean life post-split from actress Angelina Jolie.
At the time, he shared that his "kids are everything," adding that the drastic lifestyle change was not leaving him suicidal. Instead, the actor said he was feeling nothing but hopeful since getting clean.
"There's still much beauty in the world and a lot of love. And a lot of love to be given. It's all right. It's just life," he said.
In the same interview, Pitt revealed that he started therapy in 2017 after his split from Jolie one year prior.
"I love it, I love it," he told the magazine at the time. "I went through two therapists to get the right one."
Pitt appeared in good spirits on Sunday as he attended the Golden Globe Awards, where he took home the trophy for the best supporting actor for the Quentin Tarantino film.
Meanwhile, Cooper has been busy on daddy duty with his 2-year-old daughter Lea, whom he co-parents with ex Irina Shayk.