The Big Bang Theory season 10 is inching towards a cliffhanger that features a rather startling love triangle.

The finale episode titled The Long Distance Dissonance – airing on 11 May on CBS at 8pm EST – sees Sheldon Cooper's former admirer Dr Ramona Nowitzki (played by Riki Lindhome) return while girlfriend Amy Farrah Fowler is away at Princeton University for a summer research fellowship.

Lindhome's character appeared in a season 2 episode of The Big Bang Theory – as a graduate student at Caltech, who is a huge fan of Sheldon's work and has a near-obsessive crush on him.

Showrunner Steve Molaro teased that Ramona will take full advantage of the couple's long distance situation. He told TV Line, with Amy on the other side of the country "Ramona is looking to take advantage of Sheldon and he is innocently blind to it. But all of his friends are acutely aware of what's going on."

Moralo also revealed how Amy feels about Sheldon's friendship with Ramona. He told the outlet that Amy is "very unhappy". According to the showrunner, "She [Amy] tells [Penny and Bernadette] to stay on top of things on her behalf while she's 3,000 miles away."

Penny and Bernadette step up to help her friend, Amy. "They give each other a hard time and they have fights, but they really do have each others' backs," Ep said of Amy, Penny and Bernadette's friendship.

Molaro cryptically confirmed that the quasi-love triangle between Sheldon, Amy and Ramona will build to a surprising cliffhanger. "In the Big Bang writers room, we like to write stories that make us nervous. Because then it feels like it matters. Well, [this ending] is one of those," he added of 11 May finale episode.

The official synopsis for TBBT season 10 finale reads as follows:

"The gang is concerned when Sheldon's former admirer, Dr. Ramona Nowitzki (Riki Lindhome), resurfaces while Amy is away at Princeton , on the 10th season finale of The Big Bang Theory."