The 35-year-old singer surprised the crowd while joining Hayden, 26, in a performance of “Lady Marmalade” on the hit Spike series.
There is a history between the two ladies as Christina once guest-starred on Hayden‘s ABC show Nashville during season three.
Hayden was battling Eva Longoria, who performed “Anaconda” for the second round. Watch the full clip below!
Hayden Panettiere’s “Lady Marmalade” vs. Eva Longoria’s “Anaconda” | Lip Sync Battle