The showbiz world is full of middle aged leading men playing with actresses 20 years their junior.
One of the truisms of showbiz casting is that, although men may generally show some age, women must not, and must look like they are in their 20s.
Sarah Michelle Gellar is 38, so she is no longer a spring chicken, although still very attractive. Williams is 62, so he's 24 years older than she. My first daughter wasn't born until I was 27.