Bruce Jenner's sons think he is going through an ''identity crisis.''

Brody Jenner, 30, and Brandon Jenner, 32, who have been spending a lot more time with the Olympic gold medallist since he announced his split from his third wife, Kris Jenner, in October after 22 years of marriage, are reportedly concerned he recently underwent surgery to reduce the size of his Adam's apple but just want their father to be happy.

A source told gossip website ''(Bruce) is definitely having a moment.... an identity crisis, according to Brandon and Brody. They attribute it to Bruce finally being out estranged wife Kris' house.... she never would have allowed him to do this living under her roof.''

The 'Keeping Up with the Kardashians' stars haven't asked their 64-year-old father, who has also grown his hair longer recently, about his sudden desire to change his appearance but are supporting him.

The insider said: ''However, as long as Bruce is happy, that is all they really care about. Brody has been spending a lot of time with his dad, and the two have never been closer. All they know is that their dad is in a really good place right now, and that is all that matters.''

Bruce underwent a ''laryngeal shave'' procedure in Beverly Hills last month to soften the feature of his neck, which is typically done on patients who are in the first stage of gender reassignment, but insisted he only did it because he never liked his trachea.

A well-placed source on the family's E! reality series also told that there are no plans to address Bruce's new image on the show.