Isaac StoutWoah – this is going to stir things up in the Big Brother house.

Noirin’s ex has walked in, and he’s a proper hottie.

Isaac Stout, 23, is a bar owner and self-professed music producer and song writer from Ohio. He appeared on the reality show The Real World: Sydney two years ago, when he met Noirin who was travelling in Australia.

He’s one of the shaved-head exes Noirin has mentioned in the house and claims to still be in love with Noirin.

Isaac entered the house last night shouting "Daddy's back" and Noirin was obviously delighted to see him.

The hunky American was greeted with a smacker from the Irish man magnet, who told her ex: "It's so amazing to see you, I can't believe you're here.

"I'm sorry I have been kissing on national TV. God I feel sick."

So what does this mean for poor Siavash? What new depths of impotent rage can Marcus plummet to? And how will the housemates react to Isaac if Noirin goes on Friday?

So many questions… We can’t wait to watch the answers unfold.

Find out when Big Brother is on TV.