Seismic data are typically irregularly sampled along spatial axes. This irregular sampling may adversely affect some key steps, e.g., multiple prediction/attenuation or imaging, in the processing workflow. To overcome this problem almost every large dataset is regularized and/or interpolated. Our contribution is twofold. Firstly, we extend our earlier work on the nonequispaced fast discrete curvelet transform (NFDCT) and introduce a second generation of the transform. This new generation differs from the previous one by the approach taken to compute accurate curvelet coefficients from irregularly sampled data. The first generation relies on accurate Fourier coefficients obtained by an 2 -regularized inversion of the nonequispaced fast Fourier transform, while the second is based on a direct, 1 -regularized inversion of the operator that links curvelet coefficients to irregular data. Also, by construction, the NFDCT second generation is lossless, unlike the NFDCT first generation. This property is particularly attractive for processing irregularly sampled seismic data in the curvelet domain and bringing them back to their irregular recording locations with high fidelity. Secondly, we combine the NFDCT second generation with the standard fast discrete curvelet transform (FDCT) to form a new curvelet-based method, coined nonequispaced curvelet reconstruction with sparsity-promoting inversion (NCRSI), for the regularization and interpolation of irregularly sampled data. We demonstrate that, for a pure regularization problem, the reconstruction is very accurate. The signal-to-reconstruction error ratio is, in our example, above 40 dB. We also conduct combined interpolation and regularization experiments. The reconstructions for synthetic data are accurate, particularly when the recording locations are optimally jittered. The reconstruction in our real data example shows amplitudes along the main wavefronts smoothly varying with no obvious acquisition imprint; a result very competitive with results from other reconstruction methods overall.