Eminem plans to travel to his London gigs by boat to avoid protesters.
The rapper will go along the Thames under police escort for his shows at London Arena on Friday and Saturday.
He is expected to be targeted by gay rights campaigners throughout his first UK tour because his lyrics attack homosexuals.
Hip-hop duo Mark B and Blade have landed the prized support slot with Eminem at his first gig in Manchester.
The rising British stars will open at the sold-out Manchester Arena in front of 20,000 fans.
They said: "It's an honour to be on the same stage as the greatest rapper in the world at the moment.
"It's a big achievement for us. Hopefully it will break down some more doors for us."
Eminem's support for his two London dates has yet to be confirmed.
But Mark B and Blade are strongly rumoured to be in the running for the London gigs too.