Again, O.J. Simpson denies a decades-old rumor that he is Khloe Kardashian's real father (Details, pics)

The disgraced football star issued the denial when asked whether he owed Khloe any congratulations over her pregnancy while he was in Las Vegas at the weekend.

He told TMZ: 'Well, for Bob [Kardashian], God bless his soul, yeah. I don't know for me. I don't think for me I have nothing to do with it.'I would be proud ... but trust me, I had nothing to do with it.'

Khloe's parentage has long been the subject of speculation, stemming from mother Kris's infidelity and the fact that she looks different from her sisters. At the center of the speculation is joint holidays that Robert and Kris took with O.J. and Nicole Brown while both marriages were still intact.

Kris admitted cheating on Robert during her memoir. While she did not name the other man, she has previously insisted it was not Simpson.

Khloe herself addressed the rumor a 2009 episode of Keeping Up With The Kardashians when she discussed the possibility she was adopted.

The subject also formed a central threat of season 7 of the show, when she refused to take a DNA test to quash speculation. Robert's second and third wives have also fanned the flames, saying that he outright told them both that Khloe is not a Kardashian.

Neither of them suggested who the real father might be. Khloe angrily hit out at the pair after they came forward, saying: 'I think the thing that became overwhelming was when the stuff happened with one of my dad's wives.'

She wanted to come out, like, 10 years later after my dad passed away and said that I'm not his daughter and that he confided in her and blah-say-blah.

'I was like, "Listen, you can talk about me and my sisters all you f***ing want," she said, '"Do not talk about my dad … He's not here!"'Robert died in 2003 from cancer.

Jeffrey Felix, a guard at the jail where Simpson served time for armed robbery, also told how Khloe kept in touch with him while he was behind bars.

Khloe had pressured Simpson into getting a DNA test done, according to Felix, with Simpson agreeing provided she 'shows him some respect'. Felix also said that OJ confided in him that he did not sleep with Kris, saying 'I would never do that to my friend Bob.'

To date the pair have not publicly taken such a test.

When Simpson was released from jail the rumor mill restarted, with social media users targeting Khloe with mocking comments about 'her father coming home'.

Simpson was sentenced to 33 years for armed robbery for attempting to steal sports memorabilia in 2008, and was released last year.

He was famously acquitted over claims he murdered ex-wife Nicole in 1994.