Reality TV star Spencer Pratt and Playboy Playmate Karissa Shannon.(WENN.COM)

Reality TV star Spencer Pratt is facing another sex tape controversy - Playboy Playmate Karissa Shannon is threatening to sue over a video he allegedly took from her home.

Shannon's lawyer has sent a letter to the Hills star alleging he is in possession of a film that was "taken from (Karissa)" and "contains private materials" involving the glamour model and her boyfriend Sam Jones.

The Playboy star is threatening to launch a lawsuit against Pratt unless he returns the footage, reports TMZ.com.

Shannon was also embroiled in a sex tape scandal involving Pratt's estranged wife Heidi Montag last month - Pratt revealed he is in negotiations to sell racy footage of the two women in a clinch to internet porn giant Vivid Entertainment.