BB slimeball Mario Marconi will make a shock return to the house on Sunday to propose to lover Lisa, TV Biz can reveal.

He has already splashed out on an expensive ring to woo his bodybuilder girlfriend.

Show bosses will sneak him into the house to pop the question live on air.

A source said: “Mario is really excited about getting to propose to Lisa.

“He has bought a ring and can’t wait to see her again.”

Channel 4 host Davina McCall will announce the surprise visit to fans tonight following the live eviction.

But housemates will have to wait until the weekend to see Lisa’s response.

Rambo-lookalike Mario, 42, spent yesterday topping up his tan ahead of the reunion.

The oddball couple met three years ago when she bought a crystal ball from him on Internet auction site eBay.

His previous romantic gestures include pawning his Rolex to buy her a boob job.

After being evicted in week five, Mario hinted that he planned to marry Warrington lass Lisa, 40, after the show.

In reply to the big question, he smiled and said: “Possibly, yes.”

He had initially planned to ask for her hand in marriage while he was still in the house.

But he moaned that his plans were scuppered by BB with the fake wedding task.

He was forced to propose to dizzy Steph in week one instead as part of the send-up, for which an upset Lisa had to be a bridesmaid.

Mario - who claims to have bedded 200 women - later confessed: “It had been my plan to propose - and I had told someone at Big Brother.

“Then, lo and behold, within ten minutes of entering the house, I was getting married.”

As Big Brother’s first couple, Mario and Lisa were unable to keep their hands off each other in the house.

They shared a bed and were regularly seen cavorting under the covers in the luxury bedroom.

But Mario has always denied they had sex, saying: “The public shows were just pretend. It was very hard. And in the end it was very hard.”

In week eight, Lisa’s frustrations at being apart from her man boiled over when Rex’s girlfriend Nicole entered the house.

Mum-of-one Lisa smashed her way through a security door in a bid to escape. But show bosses talked her round and she went back in the house.

It will be an emotional reunion for the pair, who last saw each other when Mario got the boot almost six weeks ago.

They clashed shortly before he left with Mario calling her “Mrs Scrubber” claiming she was “too nice” to the other housemates.

But he still kissed her goodbye as he left the house after losing out to Bex in the viewer vote.

Last night a BB insider confirmed that Mario would be making a comeback.