When the Dream Weekend 2019 lineup was announced last month, the flyer featured the names and pictures of three huge acts — legendary rapper Ice Cube, hip-hop/trap trio Migos and electronic music DJ Marshmello — and the date of the event (Dec. 28). Below that, in small type, squeezed in above the venue (Aloha Stadium) was what seemed like an innocuous enough line.

“Plus more to be announced.”

The low-key nature of the five-word phrase seemed to indicate that there would be a few add-ons to fill out the festival but that the three named artists — any of whom would have a good shot at selling out Blaisdell Arena on their own — would be as big as it gets.

Who knew that “more to be announced” would include an artist with nine No. 1 hits to his name?

Today, the addition of pop/R&B superstar Usher to the bill was announced, adding considerable allure to an already stacked lineup. Also joining the show are Australian musical comedian Sammy J and rising rapper Saweetie.

Promoter Mike Galmiche said some local music fans have been taken aback by the diversity of the bill.

“Our reaction and our feedback is that they don’t quite understand it. (Because) they’re like, ‘Why is Marshmello with Ice Cube and Migos?’ It’s not the same (demographic) and genre that they’re used to, like all reggae or all country or all hip-hop.”

The lineup is modeled after festival shows such as Coachella and Burning Man, which will grab top names from all genres.

Today’s additions make what was a hip-hop-heavy lineup more rounded.

Usher has ridden his blend of soul and pop to more than 20 million in U.S. album sales since he broke out in 1997 while still a teen with the hit singles “You Make Me Wanna…” and “Nice & Slow,” his first No. 1 single. Among the eight chart-toppers he’s added since are the dance-floor bangers “Yeah!” and “OMG” and the pillowy ballads “U Got It Bad” and “Confessions Part II.”

Sammy J will open the show with his brand of satirical humor. Saweetie topped Billboard’s Rhythmic chart for the first time this year with the single “My Type,” which nearly reached the top fifth of the Hot 100. It was her second million-selling single, following 2017’s “Icy Girl.”

Tickets are available via Ticketmaster and start at $41. Front-row seats go for $500-plus, but there are general admission areas on the field without seats for much less. As with last year’s Dream Weekend, cabanas are also available for purchase.