The American singer previously opened up about their friendship in her Billboard cover story.
Daughters Blue Ivy and Rumi also shared the spotlight as the 32-date tour kicked off.
The country stinger also called the pop supernova her "North Star."
The charity gala, benefiting Children's Diabetes Foundation, will be held in October.
The British songwriter is also set to tour with Ed Sheeran across Europe this spring.
"I wouldn’t have been able to do that," the actor said.
SZA tops the Billboard 200 with SOS and the Hot 100 with “Luther” from Kendrick Lamar’s album GNX.
The veteran Welsh rocker kept up a busy touring and recording schedule even as he fought off multiple times.
The rapper chatted with Billboard to celebrate the 15th anniversary of his Kush & Orange Juice.
The account includes pictures with Taylor Swift, Harry Styles and a peek at his songwriting process.
