  Far above threshold the production process e^+e^-to t t-bar can be analyzed
using effective field theories. In this talk we consider the invariant mass
distribution of top-jets and report about our computation of the two-loop heavy
quark jet-function. This is a key part of a next-to-next-to-leading order
analysis, and already allows for a resummation of all large logs which effect
the shape of the top-invariant mass distribution at next-to-next-to-leading log
order. A top-mass scheme is defined which is suitable for measurements
involving jets, and whose anomalous dimension is determined by the
cusp-anomalous dimension to all orders in perturbation theory.
