Already one of television's most star-laden shows, HBO's "Six Feet Under" is set to welcome an assortment of new and returning guest stars for its upcoming fourth season. Currently in production in Los Angeles, the Emmy-winning hit will return to HBO this summer.

As was announced earlier, Mena Suvari will reunite with "American Beauty" screenwriter (and "Six Feet Under" creator) Alan Ball for a six-episode story arc. She'll also be joined by Ellen DeGeneres and Veronica Cartwright.

"Alien" co-star Cartwright is a regular television guest star, picking up three Emmy nominations for work on "The X-Files" and "ER." Her television career actually stretches all the way back to stints on "Leave it to Beaver" and "Daniel Boone," though she's been seen more recently in the features "Just Married" and "Scary Movie 2."

DeGeneres is still basking in the double-glow of the successful launch of her syndicated talk show and the international box office glory of her voice work in "Finding Nemo." The actress and comedian has done stand-up specials for HBO and also executive produced and co-starred in "If These Walls Could Talk 2."

In addition to the fresh faces of Suvari, Cartwright and DeGeneres, this season will feature the return of characters played by Kathy Bates, Joanna Cassidy, Patricia Clarkson, Ben Foster, Justina Muchado, Rainn Wilson and Justin Theroux.

HBO promises that still more guest stars for the 12-episode season are yet to be announced.