Iain Henderson has signed a two-year extension to his Irish Rugby Football Union contract and will remain at Ulster until 2023.
The 29-year-old second row captained Ireland for the first time against France in their last Guinness Six Nations fixture and has won 60 caps for his country.
Henderson, a British and Irish Lions tourist to New Zealand in 2017, told the IRFU website: "It has been a great honour to captain both Ulster and Ireland in recent times.
"Irish Rugby is in a good place despite the disruption the sport has experienced during the pandemic.
"As professionals we have been in a privileged position to be able to continue playing and I know we all hope to see supporters back in the Aviva and Kingspan in the near future."
IRFU performance director David Nucifora said: "Over the past few seasons Iain has really developed into a leader within both the Ireland and Ulster squads.
"He is part of the national leadership group, captaining Ireland recently for the first time and we are delighted to have ensured that he continues his career in Ireland."
Ulster captain Henderson has played 116 games for the province and his contract is entirely funded by the IRFU.