Millie Bobby Brown played "hide and seek" on her 21st birthday

She told 'Extra': "Yes, I had so much fun.

"It was a great 21st. It was amazing.

"I was with my girlfriends and my husband, and all of our friends were together, it was a big group of us.

"But we had the best time and basically just played hide and seek, and did all the things that your inner child wants to do.

"So, we were just able to hang out and have fun.

Millie stars in 'Electric State' with Chris Pratt and not only was she delighted to make a "genuine" friend, she learned a lot from her co-star's work ethic.

She said: "You rarely get to work with people that you genuinely form friendships with but when you see him on set, I've never seen anyone work like him... know every single person's name, treats everyone with respect and kindness... you just take notice of how important that is to build a family, to build a trust on a set. To be able to look up to someone who's kind of been a pro in this industry and so loved by so many people... That' s a huge inspiration to me."

And when it came to putting together her character, orphaned teenager Michelle, Millie drew inspiration from Drew Barrymore.

She explained: "I absolutely love Drew Barrymore and her hairstyle and her, just her personal day-to-day style. We used that as a lot of inspiration for the film."

Despite their young ages, the 'Enola Holmes' star recently insisted she and her 22-year-old spouse were ready for marriage before they tied the knot last year, and had spent a lot of time talking about the future before committing to one another.

She told Vanity Fair magazine: "We were pretty united going into it.

"We talked about our political views, what kind of family we want to build, the kind of home we want to live in, the kind of relationship we're looking for, the kind of careers we want.

"It's such an important decision, and we wanted to make sure we were making the right one. I knew I was. It always felt right with him."