TMZ sources claim that the Barry actor and Bilson were in Tulsa to meet up with Bill's family. Rumors about the two becoming official have been floating around for some time.
Hader and Bilson worked together previously on the comedy film The To Do List, which also starred Aubrey Plaza and Hader's longtime pal Andy Samberg. Bilson and Hader's characters had a brief relationship in the movie.
Ironically, The To Do List was written by Bill's previous wife, Maggie Carey. The two broke up in 2017 and divorced in 2018. Bilson was also previously married to Star Wars actor Hayden Christensen. Coincidentally enough, the two also split up in 2017.
It's not evident when Hader and Bilson's relationship began, nor has either party confirmed the two are dating. However, the photos found in the TMZ article seem to indicate that their relationship is starting to heat up, especially if the comedian is taking things to the next level by introducing Bilson to his family.
The photo included by TMZ shows the two walking through a Starbucks. Both of them are holding coffee cups and dressed in casual winter wear. Even though they're not holding hands in this photo, one source claimed they were at one point during their coffee date.
Hader seems to notice that someone is taking their picture as he is staring directly into the camera. Bilson has her head down as if trying to avoid being photographed or oblivious to the photographer.Fans of the duo appeared to be happy about the potential new couple, although some were a little confused.
"This confused me because I thought Rachel Bilson married Seth Cohen, but then I remembered it's Blair Waldorf," tweeted one person.
Bilson actually did date her co-star from The O.C., Adam Brody -- who played Seth Cohen -- in the past. After they broke up, Brody began dating Leighton Meester, who famously portrayed Blair Waldorf on Gossip Girl. Bilson and Meester have similar appearances.
"It must be the busiest time of year if I am just finding out about Rachel Bilson and Bill Hader this very minute," said another person.
"[I]magine casting your husband in a sex scene with rachel bilson then years later find out they're dating we are living in a simulation," joked a third user.
"[R]achel bilson is literally gorgeous omg bill won," tweeted a fourth fan.