Football - Moses, 26, who spent the previous three seasons on loan at Liverpool, Stoke and West Ham respectively, has become a regular under manager Antonio Conte.
"I feel very excited," said Nigeria international Moses.
"I'm enjoying my football and we have a good manager here that has given every single one of us confidence."
Moses, who signed from Wigan for a reported £9m in August 2012, has played 28 times, scoring four goals for the Blues this season.
He has started every Premier League game since being deployed as a right wing-back in a 3-4-3 formation in a 2-0 win away to Hull on 1 October.
Chelsea have won 16 out of 19 league games since that victory and are 10 points clear at the top of the table.