The comedian shared some fond memories of 'dancing hard' with the actress.
Fans couldn't believe the actor was actually there!
On Monday's 'Watch What Happens Live,' the actress also got candid about her rumored feud with Mariah Carey.
Tell us how you really feel, J.Lo!
Meanwhile, the 'Legends of Tomorrow' actor exclusively told ET how he reacted to Garner's Vanity Fair tell-all.
The estranged couple both attended Vanity Fair's Oscar Party, but parted ways after. ET has the details.
The actress was all smiles, even while socializing with her ex.
The actor hilariously explained how "mortifying" it was to dress up in character at his son's 4th birthday party.
The things parents do for their kids!
You have to see this to believe it.
The actor tells ET that Garner is handling the breakup "miraculously" despite dealing with "lots of stress and pain."
The actor tells ET there's still "great love" between his 'Alias' co-star and her estranged husband.
The exes put their kids first following Garner's tell-all 'Vanity Fair' interview.
The party came just one day after Garner's 'Vanity Fair' interview was revealed.
