According to TV Fodder Emily Mortimer guest-starred in the TV Series ‘30 Rock‘ in the episode ‘Corporate Crush’. She played Phoebe, an employee at Christie’s, who has the odd habit of assuming nobody remembers her, pointing it out, and introducing herself repeatedly. If you live in the US you can still catch it online at the show’s official site.

[edit] As I have just found out, Emily Mortimer will continue to guest-star as Phoebe in at least the next 2 episodes: ‘Cleveland’ (April 19) and ‘Hiatus’ (April 26). The show airs on NBC at 9.00 pm.