Nicole Richie may be less of a party girl now that she is happily married, but paparazzi still cannot take their cameras from tailing tiny Mrs. Rockstar.

On Saturday, Richie was spotted shopping for groceries with new best friend and sister-in-law, Cameron Diaz. The two Hollywood hotties looked comfortable in playing housewives while only wearing subdued outfits. Diaz sported a simple black dress with a tan cardigan and moccasin ankle boots. Her usually glamorous blonde hair tied in a messy bun.

Only Richie’s flashy, pink, pixie hairdo and mega-size sunglasses gave their celebrity status away.

New sisters-in-law @CameronDiaz and @nicolerichie shop at #WholeFoods together. http://t.co/dFv1gk6klO pic.twitter.com/dhiEFyPANa

— Yahoo Celebrity (@YahooCelebrity) March 18, 2015

“Charlie’s Angel” Diaz, who has just recently tied the knot with Benji Madden, was seen helping Richie with her grocery bags. The sisters-in-law seemed inseparable while happily doing errands for their twin husbands. Reports say that they spend more time with each other than with their spouses.

Richie has been quoted in admitting that she set up Diaz and Benji. “I am a devoted sister-in-law,” Richie told Andy Cohen, “I’m going to take responsibility for everything!”

How should @CameronDiaz and @nicolerichie celebrate Joel and Benji Madden’s birthday?: http://t.co/Y8e2evIrkN pic.twitter.com/lbiDjBueQz

— InStyle (@InStyle) March 11, 2015

Apart from being the best sister-in-law, The Simple Life star Richie seems to have mastered maturity since launching her fashion business in 2009 and then being married with Joel Madden the following year.

In an interview with Clare Press, Richie admitted to being young and crazy, saying, “I thought I was getting away with everything, when the reality was that I was arrested three times and had five car accidents. Two were totals,” she said.

Now that she is a mother of two, Richie finds life can be a lot simpler just being happy with the simple things. “I get to live my childhood all over again. My daughter is seven, so we’re starting to watch all the fun movies together, like The Sound of Music,” she said. “I believe everything in your life is an opportunity to learn and grow, and that’s what I was probably doing [back then]. It was so long ago, it’s hard for me to even think about it.”