Manny Pacquiao, who has been world champion at eight different weights, will face Argentine Lucas Matthysse for the WBA welterweight title on 14 July.
The Filipino fighter, 39, has not fought since unanimously losing the WBO version of the belt on points to Australian Jeff Horn last July.
Pacquiao has replaced long term trainer Freddie Roach with Buboy Fernandez for the contest in Kuala Lumpur, Malaysia.
Matthysse, 35, has won 36 of his 44 fights by knock-out.
Pacquiao, who is preparing for his 69th professional fight, was the first boxer in history to win world titles in four of the original eight weight classes of boxing - flyweight, featherweight, lightweight and welterweight.
Now a senator in the Philippines, Pacquiao pulled out of rematch with former schoolteacher Horn, 30, last September, and had been advised to call time on his career by Roach, who had worked with him since 2001.