Los Angeles, Dec 7 : Singer Michael Buble broke his Christmas collaboration rule as he teamed up with Cher for a new version of his 2005 single on her new festive collection, said his usual stance is to reject any offers to duet at this time of year after becoming synonymous with the season following his 2011 album 'Christmas'. He's quoted by the Daily Star newspaper's Wired column as saying: "Every late September/October every artist, the ones that you know, the biggest artists in the world, start to call me and say, 'I have an idea, you and me should make a Christmas...' And I go, (mimics putting phone down) 'click', I say, 'Thank you so much, I know you're gonna kill it.'' 'I made one Christmas record, 12 years ago! One!" He had to make an exception when the pop icon got in touch, reports aceshowbiz.com. He added: "That changes when Cher calls. Number one, when Cher calls, you pick up. And number two, she said that she wanted to cover 'Home', I wrote that song a long time ago and I am still so proud of it." Buble noted he's worked with "everyone from Justin Bieber to Barbra Streisand, to Celine Dion, to Ariana Grande, to Lady GaGa," but said Cher, whose new album "Christmas" came out in October, is "one of the greatest vocalists of our time," making it an easy decision. Meanwhile, Buble teased that he can be a bit of a Scrooge over the festive season. He joked: "When (fans) meet me and ask for a selfie or something I usually ask for $5 and they get disappointed and I'll never understand it. For the holidays, from late October to early January it's $10, the prices have gone up." /IANS