We prove a global well-posedness and regularity result of strong solutions to a slightly modified Michelson-Sivashinsky equation in any spatial dimension. Local in time well-posedness (and regularity) in the space $W^{1,\infty}$ is established and is shown to be global if in addition the initial data is either periodic or vanishes at infinity... The proof of the latter result utilizes ideas previously introduced to handle the critically dissipative surface quasi-geostrophic equation and the critically dissipative fractional Burgers equation. Namely, the global regularity result is achieved by constructing a time-dependent modulus of continuity that must be obeyed by the solution of the initial-value problem for all time, preventing blowup of the gradient of the solution. (read more)