In the episode, the singers will play themselves, performing at a fundraiser that Frank (Tom Selleck) and Erin (Bridget Moynahan) are attending. Underwood and Bennett will meet the father and daughter before singing "It Had to Be You" for the crowd. Underwood collaborated on the classic tune for Bennett's upcoming album, Duets II, which drops Sept. 20.
"The talent that they bring together is amazing," executive producer Leonard Goldberg said. "We're looking forward to an exciting second season premiere with a story that is certain to provoke debate, and are thrilled that Tony and Carrie can be a part of it."
Blue Bloods returns Friday, Sept. 23 at 10/9c on CBS.