Ian will reprise his role as Fin Shepard, while Tara will return as April Wexler alongside David Hasselhoff and Ryan Newman.
Gary Busey, Tommy Davidson, Cheryl Tiegs will also be joining the cast of the TV film, which is slated to take place five years after the last instalment, Sharknado 3: Oh Hell No!.
"Fin, his family and the cosmos have been blissfully sharknado-free in the intervening years, but now sharks - and 'nados! - are being whipped up in places (and ways) least expected...," a description of the plot reads.
The project is currently filming and will premiere on U.S. network Syfy in July (16).
The sci-fi films, which detail a freak-cyclone which lifts man-eating sharks out of the sea, gained a huge cult following after the first movie aired in 2013. While some of the cast members feel the movies are campy and ridiculous, they admit they were unaware of how big they would become.
"When I first did it, it was called Dark Skies, so I thought, 'OK, it's not gonna sound so bad on my resume... it'll be fine'," Tara said in 2014. "And then all of a sudden... they're like, 'We're changing the name to Sharknado'. I said, 'Oh my God, this is it! My career is over...' I begged them to change the name. It was horrible. They said, 'Trust us... It'll work'.
"When it came I never told anyone about it... I thought, 'OK, it's on Syfy (network), no one will ever see it'," she continued. "When it became this phenomenon, I was like, 'Are you joking me, is this really happening?'"