Lena Dunham has signed up for 'American Horror Story'.

Lena Dunham

Lena Dunham

The 31-year-old actress will join the FX show for its upcoming US Presidential election special season and co-creator Ryan Murphy cannot wait to fulfil a lifelong dream by teaming up with the 'Girls' star.

Confirming the news, Ryan tweeted: "Thrilled that my talented friend Lena Dunham is joining the AMERICAN HORROR STORY family. Always wanted to work together, and now we r! (sic)"

While details of Lena's part remain a mystery, she could appear opposite Colton Haynes after he signed up for the show last month.

Ryan announced the news on Instagram, sharing a portrait of the actor with smeared red lipstick.

He captioned the image: "Welcome to American Horror Story, Colton Haynes."

The 'Arrow' actor wrote: "American Horror Story Season 7...Already feels like home :) So excited @mrrpmurphy.(sic)"

Ryan has previously admitted the plot details for the election-themed story will be kept under wraps.

He said: "There are only three people in the world who know what it is, which is [FX president and general manager] John Landgraf, [Fox Television Group chairman and CEO] Dana Walden and Sarah Paulson."

But he has shared some hints with fans, including Colton's red lips, Billie Lourd's icy white hair and Evan Peters' blue tresses.

Lena will follow in the footsteps of the likes of Lady Gaga, who starred in the fifth season, 'American Horror Story: Hotel', and won a Best Actress Golden Globe for her part as hotel owner Elizabeth.

The 31-year-old star returned for the sixth season, 'American Horror Story: Roanoke', to play a witch named Scathach.