Hyperfine components of theR(127) line of the 11–5 band of molecular iodine at 633 nm have been observed by saturating the absorption inside the cavity of a single‐frequency He&sngbnd;Ne laser. The component widths of 4.5 MHz were broadened a factor of 2 by 1‐Torr iodine pressure, or by 500‐G magnetic field. Since no wavelength shift as large as 2 MHz was observed, wavelength perturbations from these sources should be controllable to less than 2 × 10−13&lgr;. The use of one of these components as a reference for laser stabilization is suggested.