The Blue Velvet star will play the mother of Annie Tee (Lucia Micarelli) in the third season, according to Nola.
Rossellini - the daughter of acclaimed Italian director Roberto Rossellini and Casablanca star Ingrid Bergman - previously starred in 1992 film Death Becomes Her, 1994's Wyatt Earp and 2006's Infamous.
Her past television credits include recurring roles on Alias and 30 Rock.
True Blood's Chris Coy will also appear on Treme, playing the regular role of journalist LP Everett.
The show's third season was recently pushed back by HBO, with new episodes now scheduled for late 2012.
Series creator David Simon has stated that Treme is also likely to be picked up for a fourth and final season.
> Treme creator David Simon: 'We want to be criticised'
Watch a behind-the-scenes feature on Treme below: