Diane Keaton has long been one of our favourite style icons, but we have become somewhat Diane-obsessed in recent years – starting when she appeared on The Ellen Show in 2013 discussing tantric sex and marriage. If you happened to see that broadcast, you’ll know she is a fan of red wine on ice and “the kissing of the men” (and if you haven’t seen this clip, trust us – you need to!). What we didn’t know is that she is also a total fangirl when it comes to Justin Bieber.

All was revealed as the Annie Hall actress appeared once again on Ellen DeGeneres’ daytime talk show. As the duo discussed the 21-year-old singer, Bieber himself emerged from backstage to Diane’s surprise and delight.

See her priceless reaction below: