"I love red velvet!" Reba gushed while holding the dessert.
The birthday festivities have been going strong since Saturday when Reba was celebrated at the Celebrity Fight Night XXI Founders Club Dinner at the JW Marriott Desert Ridge Resort and Spa in Phoenix. Despite it being her birthday, Reba also sang at the event, performing "I'm a Survivor" and "Going Out Like That." The latter is from Reba's new album Love Somebody, which drops April 14.
"It is a great album in my opinion," Reba told ET's Brooke Anderson. "I can say that, because I didn't write any of the songs except for one."
That song, "Pray for Peace," came to Reba in an unconventional way.
"'Pray for Peace' is a song that I got inspired to write one day when I was out walking on our place in Gallatin, Tenn.," Reba said. "The Lord just said, 'Write this song.'"
Reba's daughter-in-law Kelly Clarkson sings on the track. Even before Kelly married Reba's stepson Brandon Blackstock in 2013, Reba was already a mentor to Kelly. Their friendship dates back to 2002 when Kelly was a contestant on the first season of American Idol. Kelly called Reba "[her] American idol."
Reba is now grandmother to Kelly's 8-month-old daughter River Rose.
"We were at the iHeartRadio show last night and I was in the trailer with River and Brandon and I'd carry her around and we'd all giggle," Reba said. "She goes to anybody."
She might be a grandma, but she's not slowing down. In addition to her new album, Reba also has a Las Vegas residency this summer with iconic country duo Kix Brooks & Ronnie Dunn.
This comes after Brooks & Dunn called it quits in 2010 following a 20-year run together. The duo have a long relationship with Reba, as they opened for her in the early '90s and did a joint tour from 1997-99.
"I'm the referee," Reba said of her relationship with the two musicians. "I'm [like] the big sister that goes, 'You boys better straighten up!'"