The radio airwaves in the '90s were heavily dominated by boy bands and solo female pop artists.

Some still are.

The rivalry between Christina Aguilera and Britney Spears as teenagers just starting their careers has dwindled since Spears' head-shaving incident in 2007, but the '90s kids still know the score.

Aguilera was a guest Monday night on NBC's "The Tonight Show Starring Jimmy Fallon," where they played a game of musical impressions singing jingles and theme songs as celebrities such as Cher and David Bowie.

When Aguilera was charged with the task of impersonating Spears, Jimmy Fallon’s awkward excitement oozed and she took a second to compose herself. She then NAILED it!

Source: Free Beer & Hot Wings