The 31-year-old Zebo left Rugby Paris-based Racing 92 ahead of the current European campaign to rejoin Irish province Munster on a one-year contract.
Having been left out of Ireland’s pre-season while he took part in the French Top 14 play-offs, Zebo has been recalled for next month’s trio of Tests at Lansdowne Road.
Zebo, who has won 35 Ireland caps, effectively went into international exile when he joined Racing 92 from Munster in 2018 as the Irish Rugby Football Union generally avoids considering overseas-based players for selection.
Meanwhile Ireland captain Johnny Sexton, who also missed the victories over Japan and the United States in July, has returned to the squad and the gifted fly-half could win his 100th cap for his country against the Japanese on November 6.
Six Ireland players who were involved in the British and Irish Lions tour of South Africa are back in the squad, with Bundee Aki, Conor Murray, Iain Henderson, Jack Conan, Tadhg Furlong and Tadhg Beirne set to feature against Japan, New Zealand (November 13) and Argentina (November 21).
Robbie Henshaw has not been included in the squad but the IRFU said the Leinster centre will continue his recovery from a foot injury “under the supervision of the Ireland medical team”.
Farrell has selected uncapped Leinster hooker Dan Sheehan and centre Ciaran Frawley in his squad, while six players who made their Test debuts in July have also been included.
Ireland Rugby squad
Bundee Aki (Connacht), Robert Baloucoune (Ulster), Harry Byrne (Leinster), Joey Carbery (Munster), Craig Casey (Munster), Andrew Conway (Munster), Keith Earls (Munster), Ciaran Frawley (Leinster), Jamison Gibson Park (Leinster), James Hume (Ulster), Hugo Keenan (Leinster), Jordan Larmour (Leinster), James Lowe (Leinster), Stuart McCloskey (Ulster), Conor Murray (Munster), Garry Ringrose (Leinster), Johnny Sexton (Leinster, capt), Simon Zebo (Munster)
Ryan Baird (Leinster), Finlay Bealham (Connacht), Tadhg Beirne (Munster), Jack Conan (Leinster), Gavin Coombes (Munster), Ultan Dillane (Connacht), Caelan Doris (Leinster), Tadhg Furlong (Leinster), Cian Healy (Leinster), Iain Henderson (Ulster), Rob Herring (Ulster), Ronan Kelleher (Leinster), Dave Kilcoyne (Munster), Peter O’Mahony (Munster), Tom O’Toole (Ulster), Andrew Porter (Leinster), James Ryan (Leinster), Dan Sheehan (Leinster), Nick Timoney (Ulster), Josh van der Flier (Leinster)
Fixtures (all at Lansdowne Road, Dublin)
Nov 06: Ireland v Japan (1300 GMT)
Nov 13: Ireland v New Zealand (1515 GMT)
Nov 21: Ireland v Argentina (1415 GMT)