Block B appeared on KBS 2TV's 'Yoo Hee Yeol's Sketchbook' on April 15 and had a lot to say - including protests about leader Zico's solo activities!

Yoo Hee Yeol first said, "There's talk that Block B's comeback was pushed back because of Zico's promotions..."  The members then took turns airing their grievances.  Before that, Yoo Hee Yeol said, "Be ready today, Zico.  Now they can speak."

SEE ALSO: 'The Divorce Insurance' sweeps the charts, topping ratings from episode 1 with 5.1% peak viewership

U-Kwon complained lightly, "After getting popular through 'Show Me the Money,' he released a solo album and another solo album, and he even appeared on 'Infinity Challenge."  Park Kyung said, "Zico and I have been longtime friends.  I thought at least once he would say we should put out an album together, but he did that with other artists," appearing upset - although lightheartedly, of course.

Zico said, "Seeing as how I'm a producer, I end up looking for artists who match well musically."

Well, they're finally back!  Check out their performances below.