Hollywood writers are going on strike. The Writers Guild of America (WGA) announced late Monday night that its 11,500 members would stop working Tuesday – a decision the union’s board came to unanimously, per a tweet sent by the group’s western chapter.

The decision came after six weeks of ongoing negotiations between WGA and the Alliance of Motion Picture and Television Producers (AMPTP), an industry body representing most of Hollywood’s top studios and streaming platforms, including NBCUniversal, Netflix, Amazon, Paramount Plus, Sony, Disney, Apple and others.

Though there are still many unknowns, experts anticipate that late-night programming like Jimmy Kimmel Live and The Tonight Show with Jimmy Fallon – and its advertisers – could be among the earliest affected if WGA and AMPTP don’t reach a deal. “In terms of upcoming programming, summer is very reliant on reality programming, so there would be less of an impact, but late night will be impacted immediately,” says Stacey Stewart, US chief marketplace officer at Universal McCann, IPG’s global media agency.

Read more in The Drum.