Singer confirmed the news on his Twitter account with the following:
I would officially like to welcome
@RealHughJackman to the cast of #Xmen Days of Future Past. Very excited! More to come...
Jackman was featured in a cameo in the first movie, X-Men: First Class, which was a surprise to most movie goers. Professor Xavier and Magneto came upon Logan in a bar, who immediately told them to "bleep" off.
This time it's said that the returning X-Men cast members will not have that large of a role in X-Men: Days of Future Past as they will most likely just be featured as part of the needed future storylines.
However, as we did see Hugh Jackman appear in X-Men: First Class, it can't be ruled out that Wolverine will be featured more than the other returning X-Men characters as Wolverine has a mutant healing ability that slows his age, so he could be included in the past and the present as well.
In addition to Hugh Jackman, Patrick Stewart and Ian McKellan are in talks to reprise their characters as well, with other X-Men actors rumored including Halle Berry.
Hugh Jackman is also starring in The Wolverine, which will feature an appearance by Jean Grey, Famke Janssen.
X-Men: Days of Future Past has a July 18, 2014 release date.