The special, which also includes Adele, Leona Lewis and Miley Cyrus, will air live on Sept. 17.
Abdul has been filling in her dance card with work since Twittering her decision to quit as an "American Idol" judge. Besides the VH1 concert, she's filmed an appearance on Lifetime's "Drop Dead Diva."
Producer-judge Nigel Lythgoe of Fox's "So You Think You Can Dance" expressed interest in an Abdul cameo on the show, and ABC programming chief Stephen McPherson said he's been in touch with her.
But Abdul has yet to announce a steady job to replace the hit singing contest, which she left amid contract negotiations.