Viacom video from networks like Comedy Central, BET, MTV and Nickelodeon will be coming to T-Mobile's forthcoming streaming TV service. 

"We are thrilled to join forces with T-Mobile on a new entertainment service that represents an important evolution in how audiences consume our content," Viacom CEO Bob Bakish said in a release Wednesday. 

The deal will include both live and on-demand video.

T-Mobile's service was supposed to launch in 2018 but was delayed. The release Wednesday said Viacom channels would play a "key role" in T-Mobile's service coming to consumers "later this year."