Kate Hudson and fiance Matthew Bellamy rocked out to Elton John singing "Tiny Dancer" at iHeart Radio Music Festival in Las Vegas, Nevada on Friday, Sept. 20 Credit: Ethan Miller & Kevin Mazur/Getty Images for Clear Channel;

Penny Lane is back! Kate Hudson and her fiance, Muse frontman Matthew Bellamy, took in a performance of Elton John's "Tiny Dancer" while standing backstage at the iHeart Radio Music Festival in Las Vegas, Nevada on Friday, Sept. 20. A throwback to her breakout 2000 film Almost Famous, the adorable couple of three years paid close attention during the set.

The stunning blonde earned an Oscar nomination and A-list status playing a groupie in the Cameron Crowe film, which also starred Billy Crudup and Patrick Fugit. Based on Crowe's experience touring with rock bands, the comedy-drama showed a high-school boy (Fugit) getting the chance to write a story for Rolling Stone about an up-and-coming rock band in 1973. During a memorable scene in the movie (when the band is in an argument while driving in their tour bus) the whole gang -- including Hudson -- begins to sing John's 1971 hit.

"Muse shared a dressing room with Elton John so Matthew Bellamy and Kate Hudson were hanging out with Elton before Elton went on last night," a source reveals to Us Weekly. "They walked out with Elton on Elton's way to the stage."

Hudson, 34, and Bellamy, 35, held hands during the entire "Tiny Dancer" song. "They were kissing, holding hands, having so much fun together the whole time. Kate looked radiant!" the insider added. Bellamy and his band were also there to perform.

The couple got engaged in the spring of 2011 and welcomed their first child together, Bingham, in June 2011. The Something Borrowed star already has a second son Ryder, 9, from her previous relationship with Black Crowes singer Chris Robinson. The two were married from 2000 to 2007.