  In this letter, we consider the requirement of information freshness in
covert communications for the first time. With artificial noise (AN) generated
from a full-duplex (FD) receiver, we formulate a covertness maximization
problem under the average age of information (AoI) constraint to optimize the
transmit probability of information signal. In particular, the transmit
probability not only represents the generation rate of information signal but
also represents the prior probability of the alternative hypothesis in covert
communications, which builds up a bridge between information freshness and
communication covertness. Our analysis shows that the best transmit probability
is not always 0.5, which differs from the equal prior probabilities assumption
in most related works on covert communications. Furthermore, the limitation of
average AoI enlarges the transmit probability at the cost of the covertness
reduction and leads to a positive lower bound on the information transmit power
for non-zero covertness.
