Rapper 50 Cent says he never would have bought a Connecticut mansion once owned by boxer Mike Tyson had he realised it would require millions in repairs and renovations.

The rapper, whose real name is Curtis Jackson, testified in court as part of his lawsuit against engineers BVH Integrated Services.

50 Cent said he hired the firm to inspect the Farmington mansion in 2003 when he was buying it from Tyson’s ex-wife.

He assumed the company’s estimate of $US500,000 in repairs was “a legitimate assessment” of what the repairs would cost.

He spent about $US6 million fixing the house and says about $US3 million of that was excessive.

BVH lawyer Michael Byrne says 50 Cent wanted “extravagant and costly upgrades.”