Isaac has quit 'Big Brother'.

The American bar owner walked out of the house shortly after The Departure of ex-girlfriend Noirin yesterday (31.08.09) after being in the house just two days.

The Irish beauty had earlier admitted in her exit interview with Davina Mccall that Isaac was likely to leave, revealing they had made a pact that he would quit the show if she lost the public vote.

She said: "He's not going to stay. Absolutely sure of that. We made a decision that he's not going to stay. The only reason he came here was to be with me and get me away from Siavash. If he wants to stay, he wants to stay, because he thinks he might win."

Despite earlier claiming he had entered the show to win, the former 'Real World Sydney' star joined his former beau on spin-off programme 'Big Brother's Big Mouth' just after her departure.

Despite having split up before Noirin entered the house, the 25-year-old retail manager - who had a brief romance with Siavash until Marcus' shock arrival in the house - regularly spoke about her former love, who had admitted he was still in love with her.