The singer who was off the radar for a minute while she worked on her new album had quite the busy weekend.On Saturday she completed two nights of concerts at the Rose Bowl in Los Angeles as part of her "Reputation" tour.Naturally celebs turned out to catch T-Swift doing her thing."If you enjoy pleasure even a little bit then go see @taylorswift13 Reputation Tour," tweeted actress Lena Dunham, who was in attendance. "It's heaven front to back and I'm not just saying that cuz she lets me cry in her lap."Also there were actress Sarah Michelle Gellar, basketball superstar Kobe Bryant and his wife Vanessa and model/actress Amber Rose who snapped a selfie backstage with Swift and actresses Julia Roberts and Rebel Wilson.Swift kept the star power up on stage with guest appearances by singer/songwriter Troye Sivan and Swift's bff Selena Gomez.She and Gomez performed the latter's hit "Hands to Myself" and Gomez praised her longtime friend as one who has "never ever judged a single decision I've made.""She's always met me where I've been," Gomez said. "She's encouraged me when I've had nothing to be encouraged about, and I don't know if I would be as strong as I am if I didn't have you and your family because you've changed my life."On Sunday Swift was off to the Billboard Music Awards in Las Vegas where she snapped photos with the likes of supermodel Tyra Banks and served up a meme of the night jokingly rolling her eyes and looking at her nails before laughing and singing along to host Kelly Clarkson's covering her hit "Look What You Made Me Do" during the opening medley.Swift, who picked up awards for top selling album and female artist, also had a funny moment with actor Darren Criss.Billboard Music Awards 2018: Check out the complete list of winnersThe "American Crime Story: The Assassination of Gianni Versace" star tweeted a video of Swift and a friend appearing to block his view as singer Shawn Mendes performed during the awards show."Uh Miss … excuse me, Miss," Criss is seen saying in the video to an oblivious Swift who has her back to him. "Miss, I can't see. I'm trying to watch Shawn Mendes!"