Scarlett Johansson makes her new relationship official!

Actress Scarlett Johansson takes beau Sean Penn to Reese Witherspoon’s wedding. Johansson has made her romance with Sean Penn official — by taking him to Reese Witherspoon’s wedding!

Witherspoon tied the knot with Hollywood agent Jim Toth over the weekend.

“Scarlett is Jim’s client, but no one, including the bride, knew she would have turned up with Sean Penn,” a source told PopEater.

“Turning up at a wedding with your boyfriend is definitely a huge statement, especially that wedding. What it’s doing is announcing to the whole of Hollywood that they are serious.”

Also in attendance at the private wedding were Renee Zellweger, Tobey Maguire, Robert Downey Jr. and Alyssa Milano.

“Scarlett is head over heals in love with Sean,” the source added. “She normally tries to hide away from public attention, but when she’s with Sean she doesn’t care.”

Johansson and Ryan Reynolds, 34, split in December after two years of marriage. In August of 2009, Robin Wright, 44, filed for divorce from Penn. The couple had been married 13 years.

Scarlett and Sean were first linked last month.

“Scarlett first reached to Sean when she was planning to visit Haiti with Oxfam,” a source told Us Weekly magazine.

“She knew Sean was living there in a tent and turned to him for advice.

“Scarlett’s smitten with him.”