The pair were announced this week to be among the performers at the 54th awards ceremony.
The duo will perform a version of the standard 'It Had To Be You', with Underwood describing the 85-year-old singer as "America's most enduring artist".
Tony Bennett performed at the very first Grammy Awards in 1959, and he revealed that he still enjoys the event.
"I've been on every single one that we've had through the years," he told The AP. "And what I love about it, this is the only place where all the performers get together in one weekend, and it's so great to see old friends and new guys that are coming up."
Speaking about Carrie Underwood's talents, he added: "She's beautiful and she sings great and she's so popular. It's just a wonderful experience to be on the show."
The Grammy Awards will see a unique group performance by nominees Chris Brown, Deadmau5, Foo Fighters, David Guetta and Lil Wayne during the evening.
> Tony Bennett won't retire: 'I have a desire to get better with age'
Listen to Tony Bennett and Carrie Underwood perform 'It Had To Be You' from Duets II below: