Heidi Montag and Spencer Pratt have reportedly signed up for 'Celebrity Big Brother'.

Spencer Pratt and Heidi Montag

Spencer Pratt and Heidi Montag

The reality TV stars - who got married in 2009 - have reportedly taken pen to paper and scribbled a six-figure deal to take part in the forthcoming 'Gold Stars vs All Stars'.

A source said: "Spencer and Heidi are very competitive and they got so close to winning last time that they're hell bent on coming out on top this time around."

It's believed Heidi and Spencer were at the top of bosses' lists for the spin-off, which kicks off in January and will see old housemates take on new contestants, as they know they'll struggle to hold their tongues when put against other strong characters, because they proved such a hit with viewers when they took part in the series in 2013.

The insider told Daily Star newspaper: "Last time they were not sure what to expect, but they've become big fans of the show since their stint in the house. And they're sure they've devised the secret strategy that will see them win it. They will be even sneakier and more manipulative than last time, and won't hesitate to throw anyone under the bus."

The full line up for the spin-off is yet to be announced but James Jordan - who wasn't afraid to let loose with his acid tongue in 2014 - and Jasmine Lennard, who appeared on the show in 2012, have also been in talks with bosses about starring in the special.

A source said recently: "Channel 5 approached James with a six figure deal.

"The producers loved how feisty he was when he appeared on 'Celebrity Big Brother' in 2014 and they know he won't hold back. Bringing in big personalities like James and Jasmine makes great TV and there could be a clash between the two of them."