A new type of a two-dimensional system of He-4 atoms localized near a
solid wall in liquid He-3 is considered. It is swown that two-dimensio
nal second sound waves can propagate in He-4 layer in superfluid He-3.
At low enough temperatures the sheet of He-4 atoms can transit to sup
erfluid state realizing the situation when two superfluid liquids cc-e
xist.