Tennis fans were thrilled to see Roger Federer attending Coldplay's "Music of the Spheres World Tour" concert at the Letzigrund Stadium in Zurich and singing along with Chris Martin and the band on stage.Federer is thoroughly enjoying his life after retirement. On Sunday, the Swiss legend attended the concert in Zurich. He was graciously invited on stage by Chris Martin himself, to join the band and play the shaker in perfect harmony with their iconic song, "Don't Panic."The 20-time Grand Slam champion effortlessly synchronized his shaker with the band's melodious tunes. Not only did Roger Federer showcase his musical talents, but he also surprised the audience by singing along with Chris Martin and the rest of the band.Relevant Tennis@RelevantTennisROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! #ColdplayZurich869126ROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! 😭🇨🇭#ColdplayZurichhttps://t.co/MPWtrXfeN2Tennis fans were absolutely thrilled to witness the 41-year-old performing alongside Coldplay on stage. They took to social media to express their elation. One fan remarked that the tennis legend appeared to be relishing his life after retirement, engaging in unexpected and exciting endeavors."Roger really is just completing these random side quests," a fan tweeted.Henry@WannaTalkAbout4@RelevantTennis Roger really is just completing these random side quests13@RelevantTennis Roger really is just completing these random side questsAnother fan stated that the people in attendance were very fortunate to witness both Coldplay and Roger Federer sharing the same stage."U R IN THEE COLDPLAY CONCERT N U GET TO SEE THE GOAT ON STAGE. WHEN IS MY TURN??" the fan tweeted.Asmaa Corduva@corduva77U R IN THEE COLDPLAY CONCERT N U GET TO SEE THE GOAT ON STAGEWHEN IS MY TURN?? twitter.com/RelevantTennis…Relevant Tennis@RelevantTennisROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! #ColdplayZurich870127ROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! 😭🇨🇭#ColdplayZurichhttps://t.co/MPWtrXfeN2U R IN THEE COLDPLAY CONCERT N U GET TO SEE THE GOAT ON STAGEWHEN IS MY TURN?? twitter.com/RelevantTennis…Here are a few other reactions:Rob Koenig@RobKoenigTennis“Our original band member, Roger Federer.” Chris Is such a legend with bringing locals on stage…. twitter.com/relevanttennis…Relevant Tennis@RelevantTennisROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! #ColdplayZurich12415ROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! 😭🇨🇭#ColdplayZurichhttps://t.co/MPWtrXfeN2“Our original band member, Roger Federer.” Chris Is such a legend with bringing locals on stage…. twitter.com/relevanttennis…Hioara Vera@m_verushka#Federer enjoying his life after tennis )... twitter.com/RelevantTennis…Relevant Tennis@RelevantTennisROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! #ColdplayZurich876129ROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! 😭🇨🇭#ColdplayZurichhttps://t.co/MPWtrXfeN2#Federer enjoying his life after tennis 👏👏👏)... twitter.com/RelevantTennis…𝕋𝕚𝕡𝕡𝕚𝕟 𝕠𝕟 𝕙𝕒𝕣𝕕𝕨𝕠𝕠𝕕 𝕗𝕝𝕠𝕠𝕣𝕤@E_Teezey1286Fed out here really doing side quests to 100% life twitter.com/relevanttennis…Relevant Tennis@RelevantTennisROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! #ColdplayZurich876129ROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! 😭🇨🇭#ColdplayZurichhttps://t.co/MPWtrXfeN2Fed out here really doing side quests to 100% life twitter.com/relevanttennis…Tennis Legacies@TennisLegaciesBetween this and being my new navigation voice on @waze, @rogerfederer is already off to an incredible post retirement career. The man clearly knows how to have fun. I miss him on the court, but I’m happy he hasn’t disappeared! twitter.com/relevanttennis…Relevant Tennis@RelevantTennisROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! #ColdplayZurich877129ROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! 😭🇨🇭#ColdplayZurichhttps://t.co/MPWtrXfeN2Between this and being my new navigation voice on @waze, @rogerfederer is already off to an incredible post retirement career. The man clearly knows how to have fun. I miss him on the court, but I’m happy he hasn’t disappeared! twitter.com/relevanttennis…Pranava@RedGeneral18Idk what cross over this is but NOBODY is complaining… twitter.com/relevanttennis…Relevant Tennis@RelevantTennisROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! #ColdplayZurich877129ROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! 😭🇨🇭#ColdplayZurichhttps://t.co/MPWtrXfeN2Idk what cross over this is but NOBODY is complaining… twitter.com/relevanttennis…lana@phonzyalagoat doing goat things twitter.com/relevanttennis…Relevant Tennis@RelevantTennisROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! #ColdplayZurich1129ROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! 😭🇨🇭#ColdplayZurichhttps://t.co/MPWtrXfeN2goat doing goat things twitter.com/relevanttennis…Ahmad M. Othman@AhmadMOthman14This sounds like a dream. twitter.com/RelevantTennis…Relevant Tennis@RelevantTennisROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! #ColdplayZurich877129ROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! 😭🇨🇭#ColdplayZurichhttps://t.co/MPWtrXfeN2This sounds like a dream. twitter.com/RelevantTennis…Hugo Ribeiro@hugo17ribeiroI'M CRYING twitter.com/RelevantTennis…Relevant Tennis@RelevantTennisROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! #ColdplayZurich877129ROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! 😭🇨🇭#ColdplayZurichhttps://t.co/MPWtrXfeN2I'M CRYING twitter.com/RelevantTennis…Con Haidemenos@HaidemenosConMiss this guy twitter.com/relevanttennis…Relevant Tennis@RelevantTennisROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! #ColdplayZurich877129ROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! 😭🇨🇭#ColdplayZurichhttps://t.co/MPWtrXfeN2Miss this guy twitter.com/relevanttennis…Christopher Johnson (The Globalite)@globalitemanThe irony is that musicians like myself (and Coldplay) don't have to retire due to age or injury. I hope #Federer keeps working on his shaker solos. twitter.com/RelevantTennis…Relevant Tennis@RelevantTennisROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! #ColdplayZurich2129ROGER FEDERER JOINED COLDPLAY ON STAGE TO PLAY & SING 'DON'T PANIC'! 😭🇨🇭#ColdplayZurichhttps://t.co/MPWtrXfeN2The irony is that musicians like myself (and Coldplay) don't have to retire due to age or injury. I hope #Federer keeps working on his shaker solos. twitter.com/RelevantTennis…"I'm often on the court with the children, love playing with them" - Roger FedererQatar ExxonMobil Open 2021 - Day ThreeIn a recent interview with Tages-Anzeiger, Roger Federer shared that since retiring he only plays tennis with his children, Charlene Riva, Myla Rose, Leo, and Lenny, as he cherishes the opportunity to spend quality time with them on the court."Only with the children. I've never booked a court with friends and said, 'Come on, let's go train now.' But I'm often on the court with the children. I love playing with them," he said.Simon Graf@SimonGraf1Does he still play tennis? «Only with the children. I've never booked a court with friends and said, "Come on, let's go train now." But I'm often on the court with the children. I love playing with them.» (8/10)10613The Swiss also admitted that he continues to frequently check tennis scores throughout the day, even though he is no longer an active player. He acknowledged that his demanding schedule, which includes traveling and spending time with his children, often leaves him with limited time to stay updated on the latest scores."I'm very surprised at how often and how frequently I check the scores, three times a day maybe, then, of course, all of a sudden, there's days where I check out for like a week. I'm with the kids, and then I'm traveling, and I'm gone, and, you know, you forget about everything around yourself," he added.Federer, 41, retired in September last year, playing his final match at the Laver Cup.