Watch : Hot Goss: Can Someone Tell Us What's Going on Between Anna Kendrick & Blake Lively? Blake Lively thinks Anna Kendrick's singing voice is a favor to all. The Gossip Girl alum shared her amazement at her Another Simple Favor costar's vocals after the Pitch Perfect alum participated in a game on The Tonight Show Starring Jimmy Fallon.

"Math: @annakendrick = one of one," Blake wrote on her April 30 Instagram story, where she shared a video of Anna singing Hanson's "MMMBop" to the tune of Benson Boone's "Beautiful Things" for the "Song Scrambler" singing challenge. "This woman. INSANELY talented."

"I meannnn," she continued, "It's bonkers." Blake added, "I want this as my ringtone please and thank you." Isaac Hanson himself agreed, writing in the comments on the original post, "you sounded fantastic… Well done!

I love this!" The It Ends With Us star's compliment comes shortly after Blake, 37, and Anna, 39, reunited in London on April 15 while promoting their sequel film, Another Simple Favor.