This paper reports on the discovery and analysis of PSR J0514−4002E, an eccentric binary millisecond pulsar in the globular cluster NGC 1851. The pulsar has a total binary mass of 3.887 ± 0.004 solar masses (M⊙), with its companion being a compact object with a mass between 2.09 and 2.71 M⊙. This mass range places the companion in the mass gap between neutron stars (NSs) and black holes (BHs), suggesting it could be either a very massive NS or a low-mass BH. The authors propose that the companion was formed by the merger of two earlier NSs. The study utilized observations from the MeerKAT radio telescope to determine the spin, astrometric, and orbital parameters of the pulsar. The timing model derived from these observations revealed a high total system mass, indicating the presence of a compact object. Further analysis, including near-ultraviolet and optical observations, ruled out the possibility of the companion being a main-sequence star, confirming its compact nature. The measured rate of periastron advance is purely relativistic, leading to an estimated total system mass of 3.887 ± 0.004 M⊙, which is 1.0 M⊙ larger than the mass of the most massive double NS known. The companion mass is likely in the mass gap, being higher than the largest precisely measured pulsar masses but below the observed minimum mass of about 5 M⊙ for BHs in Galactic X-ray binaries. The authors suggest that the companion could have formed in a NS-NS merger event, regardless of whether it is a NS or BH. The dense core of NGC 1851 increases the probability of such mergers occurring. The study also discusses the orbital inclination angle and the nature of the companion, concluding that the companion is likely a compact object with a mass in the mass gap.This paper reports on the discovery and analysis of PSR J0514−4002E, an eccentric binary millisecond pulsar in the globular cluster NGC 1851. The pulsar has a total binary mass of 3.887 ± 0.004 solar masses (M⊙), with its companion being a compact object with a mass between 2.09 and 2.71 M⊙. This mass range places the companion in the mass gap between neutron stars (NSs) and black holes (BHs), suggesting it could be either a very massive NS or a low-mass BH. The authors propose that the companion was formed by the merger of two earlier NSs. The study utilized observations from the MeerKAT radio telescope to determine the spin, astrometric, and orbital parameters of the pulsar. The timing model derived from these observations revealed a high total system mass, indicating the presence of a compact object. Further analysis, including near-ultraviolet and optical observations, ruled out the possibility of the companion being a main-sequence star, confirming its compact nature. The measured rate of periastron advance is purely relativistic, leading to an estimated total system mass of 3.887 ± 0.004 M⊙, which is 1.0 M⊙ larger than the mass of the most massive double NS known. The companion mass is likely in the mass gap, being higher than the largest precisely measured pulsar masses but below the observed minimum mass of about 5 M⊙ for BHs in Galactic X-ray binaries. The authors suggest that the companion could have formed in a NS-NS merger event, regardless of whether it is a NS or BH. The dense core of NGC 1851 increases the probability of such mergers occurring. The study also discusses the orbital inclination angle and the nature of the companion, concluding that the companion is likely a compact object with a mass in the mass gap.