Ellen DeGeneres. Picture: Supplied

Ellen DeGeneres alleges she was sexually assaulted as a teenager.

The 61-year-old star has spoken candidly about the traumatic experience which she alleges occurred after her mother Betty married "a very bad man" and was diagnosed with breast cancer shortly afterwards.

Speaking on Netflix show 'My Next Guest Needs No Introduction With David Letterman', she said: "He told me when she was out of town that he'd felt a lump in her breast and needed to feel my breasts because he didn't want to upset her, but he needed to feel mine.

"Again, because I didn't know about bodies, I don't know that breasts are all different and ... Anyway, he convinced me that he needs to feel my breasts and then he tries to do it again another time, and then another time."

The daytime talk show host - who explained her mother Betty is "apologetic" about everything - also added she didn't want to tell her mum about the incident at the time because she "knew that would ruin her happiness".

Revealing why she has chosen to open up about the alleged abuse now, she said: "I'm angry at myself because, you know, I didn't … I was too weak to stand up to … I was 15 or 16.

"It's a really horrible, horrible story and the only reason I'm actually going to go into detail about it is because I want other girls to not, you know, ever let someone do that ... I should never have protected her.

"I should have protected myself and I didn't tell her for a few years and then I told her. And then she didn't believe me and then she stayed with him for 18 more years. And finally left him because he'd changed the story so many times."

Bang Showbiz