The Briton comes into the line-up in the #22 United ORECA-Gibson 07 alongside long-time team-mates Albuquerque and Hanson in place of Will Owen as the silver-rated driver.
Lubin is making the switch to sportscar racing after a season in Euroformula Open in which he took one win on the way to fourth in the championship with Team Motopark.
He told Motorsport.com: “One of my dreams has always been endurance racing, so I’m delighted to get the chance with a team like United.
“The next step in single-seaters would have been Formula 3, but that’s silly money and would have to be a two-year project.
“But it’s not impossible that I could do some endurance stuff and then go back to single-seaters.”
United team boss Richard Dean said that Lubin impressed during a one-day test aboard one of the team’s Orecas at the Portimao circuit in October.
“We had Phil there as a reference and Freddie performed really well,” he said.
“We ran him through a proper programme over the course of the day, including race and qualifying runs, and he took it all in and did a super job.”
United now has its full roster of drivers for its 2023 WEC campaign.
The #23 Oreca will be raced by Tom Blomqvist, Oliver Jarvis and Josh Pierson.
Giedo van der Garde will sub for Blomqvist when the Briton is on duty with the Meyer Shank Racing Acura team in the IMSA WeatherTech SportsCar Championship.
Aubry back to LMP2 with Vector
Gabriel Aubry will return to LMP2 in the WEC in 2023 with the Vector Sport team.
The Frenchman, a multiple WEC P2 race winner, is making his P2 comeback in the series aboard the solo Vector Oreca 07-Gibson after a year racing in GTE Am in 2022.
Aubry dovetailed a WEC campaign with AF Corse's sister team Spirit of Race, driving a Ferrari 488 GTE Evo with a season racing in P2 in the European Le Mans Series with Team Virage.
The 24-year-old raced in the WEC with the JOTA-run Jackie Chan DC Racing squad in 2018/19 and 2019/20, taking second place in the championship in the first of those seasons and a total of four class victories.
Aubry has been announced by Vector for its second season in the WEC along with Matthias Kaiser.
The silver-rated Lichtenstein driver, 32, is moving over to the WEC after a year racing in P2 in the ELMS with Muhlner Motorsport.
Vector team boss Gary Holland said: “We are delighted to welcome Gabi and Matthias to the team.
“We’re confident their individual qualities, drive and determination will help us continue to make a mark in what we know is going to be an intensely competitive season.”
Ryan Cullen, who drove with Sebastien Bourdais and Nico Muller at Vector last season, was listed by the team when the WEC entry was announced in January but was not mentioned in the latest statement.
It is expected he will be in the car for the season-opener at Sebring on 17 March and will play a key role in development of the Isotta Fraschini Le Mans Hypercar ahead of its likely race debut with Vector later this season.
