It's Always Sunny In Philadelphia: 10 Cameos You (Probably) Missed
3. Nora Dunn
Nora Dunn plays Donna, Dee and Dennis' maternal aunt and Frank's sister-in-law, in Season 5, Episode 4, "The Gang Gives Frank an Intervention." In the episode they go to her husband's funeral, where both Frank and Mac try to hit on the newly widowed woman. She blows them both off.
Dunn got famous for her time on Saturday Night Live in the 80s. Her work since then has included roles in movies such as Pineapple Express and Bruce Almighty.