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The pair come from opposing sides of the Brexit argument
The former Home Secretary Amber Rudd has appealed to Conservative colleagues to assist Theresa May when the Commons votes once more on the EU withdrawal invoice.
In a present of unity, Remainer Ms Rudd has co-authored a piece in Sunday's Telegraph with Brexiteer Iain Duncan Smith, calling on MPs to back the PM.
Backing the invoice was a "no brainer" and important to delivering Brexit, they mentioned.
The invoice returns to the Commons subsequent week as ministers attempt to overturn amendments made by the House of Lords.
In the joint article, the pair say the withdrawal invoice is "not about competing visions of the future but about ensuring legal certainty at our point of departure".
They known as on colleagues "to demonstrate discipline and unity of purpose".
"We cannot allow ourselves to become divided and risk losing the precious chance to go on implementing policies that transform lives."
If sufficient Tory MPs determine to vote with Labour and different opposition events, the federal government might be defeated on a number of key votes.
More than a dozen rebels might vote in favour of amendments supposed to hold the UK in a customs union with the EU.
Remaining in such an association after Brexit is now Labour's place, so any Tory rebel might spell defeat for the federal government.
In the Telegraph piece, Ms Rudd and Mr Duncan Smith mentioned Labour could be fast to exploit any authorities setback.
"Jeremy Corbyn will do everything he can to stop us," they warned.
"That includes cynically trying to frustrate the Brexit process for his own political ends."
Conversely, the federal government could also be boosted by assist from a handful of pro-Brexit Labour MPs.
While ministers are assured of profitable many of the votes, the opposite modification elevating concern is the one which defines Parliament's function on the finish of the Brexit negotiations.
Appealing to these in the Tory Remain camp, the federal government says MPs can have loads of alternatives in coming months to take into account and vote on all facets of Brexit, together with any remaining deal that Mrs May negotiates.
But Sunday's Telegraph article stresses: "The disagreements in the party do not extend to whether we should leave, only how we do it".
Their feedback echoed Mrs May herself, who, talking on the G7 summit, accused lords of going "far beyond" their function with their amendments to the withdrawal invoice.
"Let's remember what the withdrawal bill is for: it's about delivering a statute book that is ready for Brexit day."
"This government is delivering on the decision made by the country in the referendum to leave the EU and we will not accept anything that prevents us from taking back control of our money, laws and borders."