Just hours after Sinead O'Connor wrote an open letter to Miley Cyrus that she's "extremely concerned" for her, the "We Can't Stop" singer responded by comparing her to Amanda Bynes, and recalling O'Connor's infamous 1992 Saturday Night Live appearance Credit: James Devaney/WireImage.com; Phillip Massey/FilmMagic

Miley Cyrus is giving Sinead O'Connor a taste of her own medicine. Just hours after O'Connor, 46, penned a lengthy open letter to Cyrus about her outlandish behavior and how's she's apparently prostituting herself, the "We Can't Stop" singer shared a photo of O'Connor's 1992 infamous moment when she ripped a picture of the Pope on Saturday Night Live. "#SNL," Cyrus simply wrote alongside the photo on Thursday, Oct. 3. 

Top top it off, Cyrus, 20, also compared O'Connor to none other than Amanda Bynes. "Before Amanda Bynes.... There was…" the Bangerz star wrote. Alongside the comment, Cyrus posted a screenshot of tweets from O'Connor's old Twitter account from two years ago. Some of the tweets included the Irish singer trying to find a psychiatrist in Ireland who could "urgently" see her as soon as possible. (Bynes' parents gave an update on their 27-year-old daughter on Sept. 30 that she's "making great strides towards recovery" since moving to celebrity rehab center The Canyon in Malibu three weeks ago.)

Good timing? The "Wrecking Ball" singer cleverly pointed out the provocative photo and tweeted the Bynes diss just days before hosting SNL herself. Could a possible O'Connor sketch be in the works?