Later that year, she appeared in her first film since "Grease", starring in the musical "Xanadu" with Gene Kelly and Michael Beck. Although the film was a critical failure, its soundtrack (No. 4 Pop) was certified double platinum and scored five top 20 singles on the "Billboard" Hot 100. Newton-John charted with "Magic" (No. 1 Pop, No. 1 AC), "Suddenly" with Cliff Richard (No. 20 Pop, No. 4 AC) and the title song Xanadu with the Electric Light Orchestra (No. 8 Pop, No. 2 AC). (ELO also charted with "I'm Alive" (No. 16 Pop, No. 48 AC) and "All Over the World" (No. 13 Pop, No. 46 AC).)   "Magic" was Newton-John's biggest Pop hit to that point (four weeks at No. 1) and still ranks as the biggest AC hit of her career (five weeks at No. 1). The film has since become a cult classic and the basis for a Broadway show that ran for more than 500 performances beginning in 2007 and was nominated for four Tony Awards including Best Musical. (A successful international tour of the show followed.) In 1981, Newton-John released her most successful studio album, the double platinum "Physical", which strongly reinforced her image change by showcasing risqué, rock-oriented material. Newton-John explains: "I just wasn't in the mood for tender ballads. I wanted peppy stuff because that's how I'm feeling." Of the titular cut, Newton-John says: "Roger Davies was my manager at the time; he played it for me and I knew it was a very catchy song." In fact, the title track, written by Steve Kipner and Terry Shaddick, spent ten weeks atop the "Billboard" Hot 100, matching the record at that time for most weeks spent at No. 1 in the rock era held by Debby Boone's "You Light Up My Life". The single was certified platinum and it ultimately ranked as the biggest song of the decade. (In 2008, "Billboard" ranked the song No. 6 among all songs that charted in the 50-year history of the Hot 100.)  "Physical" earned Newton-John her only placement ever on the R&B Singles (No. 28) and Albums (No. 32) charts. The "Physical" album spawned two more singles, "Make a Move on Me" (No. 5 Pop, No. 6 AC) and "Landslide" (No. 52 Pop).