Nicki Minaj has opted against joining Rihanna’s Last Girl on Earth Tour this summer.

The Queens MC broke the news to her fans on Twitter this afternoon [April 7]. “Barbz I’m sorry 2 say I will not be going out on RiRi’s tour,” she wrote on Twitter. “I’ve decided 2 use that time 4 the completion of my album. Hope u understand.”

And she has been hard at work on the disc. Minaj recently premiered the video for “Massive Attack,” the first single off her as-yet-untitled album last week.

Although she won’t be joining the 25-city tour, you can still catch the Harajuku Barbie alongside her Young Money partner Drake on the cover of the May 2010 issue of XXL, which hits stands nationwide on April 20. —Brooklyne Gipson