Those two rival companies are strange bedfellows in this new project.
strange bedfellows
idiomAn unusual combination or political alliance.
Origin
first recorded 17th c.1610, from Shakespeare's The Tempest.
The environmental group and the oil company became strange bedfellows to support the new tax law.
In the volatile world of local politics, the radical activist and the conservative mayor proved to be strange bedfellows during the recent election.