Norwegian driver Ostberg, a mainstay of the WRC from 2011 until 2018, will contest the full eight-round WRC2 schedule at the wheel of a PH Sport-run Citroen C3 R5.
It follows his campaign in the second-tier series, known last year as 'WRC2 Pro', in a factory-entered Citroen that yielded three wins and second in the points behind Kalle Rovanpera.
Citroen's works WRC2 team was discontinued for 2020 along with its top-level effort, although the C3 R5 continues to be made available for customer teams.
“It’s great to be continuing with everyone in the team," said Ostberg. "We worked hard on the car’s development last year, with the main evolutions notably concerning its brakes, suspension and engine performance. That should give us a certain edge in 2020.
"Along with Torstein [Eriksen, co-driver], our aim is to win as many rounds as possible and claim the title. I can hardly wait for this year’s Rallye Monte-Carlo to get the season underway. We will do our absolute best to come away with a strong result.”
Citroen will also support Yohan Rossel in the WRC3 class (previously known as WRC2) this year, with four more C3 R5s on the entry list for the Monte Carlo season opener, including one for former M-Sport Ford WRC driver Eric Camilli.
M-Sport has announced it will field two Fiesta R5s in WRC2 this season for Frenchman Adrien Fourmaux and Briton Rhys Yates.