In this study, an innovative technique is introduced to significantly enhance the sensitivity of electronic speckle pattern interferometry (ESPI) for the dynamic assessment of specular (mirrorlike) object deformations. By utilizing a common-path illumination strategy, wherein illumination and observation beams are precisely aligned, this method effectively doubles the optical path difference, leading to a twofold increase in measurement sensitivity. In addition, this method mitigates the effects of speckle noise on the measurement of minor deformations, expanding the applications of ESPI. Theoretical and experimental evaluations corroborate the efficacy of this approach.