Billboard reports that Allen, 29, will team up with the "Wrecking Ball" singer for seven shows of her tour beginning August 1 in Uniondale, N.Y.
Sky Ferreira and Icona Pop previously opened for Cyrus and Allen will be joining the singer for the rescheduled dates that resulted from Cyrus' April hospitalization over an extreme allergic reaction.
Allen will kick off her own tour on Sept. 9 in Miami, less than a month after her last opening show for Cyrus.
You can check out the dates and locations of the duo's upcoming performances below.
Aug. 1: Uniondale, N.Y. (Nassau Veterans Memorial Coliseum)
Aug. 2: Philadelphia, Pa. (Wells Fargo Center)
Aug. 4: Pittsburgh, Pa. (CONSOL Energy Center)
Aug. 6: Charlotte, N.C. (Time Warner Cable Arena)
Aug. 7: Nashville, Tenn. (Bridgestone Arena)
Aug. 9: Louisville, Ky. (KFC Yum! Center)
Aug. 10: St. Louis, Mo. (Scottrade Center)