The UFC is expected to announce the 135-pound title bout soon. UFC 227 will take place at Staples Center. The placement of the fight on the pay-per-view card is yet to be determined.
Dillashaw (15-3) is a two-time bantamweight champion. He held the title from 2013 to 2016, when he surrendered it to Dominick Cruz in a narrow split-decision loss.
Fighting out of Denver, Dillashaw reclaimed the belt by knocking out rival and former training partner Garbrandt at UFC 217 in November. The two trained alongside each other at Team Alpha Male in Sacramento before Dillashaw left for Colorado.
Garbrandt (11-1) has won six fights in the UFC, including four by knockout. He hurt Dillashaw with punches early during their November meeting, but the tide turned in the second round.