Complete fusion of two selected cells allows for the creation of novel hybrid cells with inherited genetic properties from both original cells. Alternatively, via fusion of a selected cell with a selected vesicle, chemicals or genes can be directly delivered into the cell of interest, to control cellular reactions or gene expression. Here, we demonstrate how to perform an optically controlled fusion of two selected cells or of one cell and one vesicle. Fusion is mediated by laser irradiating plasmonic gold nanoparticles optically trapped between two cells (or a vesicle and a cell) of interest. This hot-particle-mediated fusion causes total mixing of the two cytoplasms and the two cell membranes resulting in formation of a new hybrid cell with an intact cell membrane and enzymatic activity following fusion. Similarly, fusion between a vesicle and a cell results in delivery of the vesicle cargo to the cytoplasm, and after fusion, the cell shows signs of viability. The method is an implementation of targeted drug delivery at the single-cell level and has a great potential for cellular control and design.