While the starting lineups of the Mets and Phillies will get most of the attention at this weekend's London Series presented by Zoom Workplace -- who isn't looking forward to a possible Bryce Harper or Pete Alonso blast over the London Stadium wall? -- that's not the only action you'll find on the field this weekend.

Before you head out to the ballpark -- or throw the game on your TV -- here are a few more things going on at London Stadium that you should keep an eye on.

• Everything you need to know for the London Series

Jess Glynne headlines

Be sure to get into your seats early because before Sunday's 3 p.m. BST / 10 a.m. EST start time, because Grammy Award-winning artist Jess Glynne will be performing. Known for her hits "Hold my Hand," "Rather Be," and "Don't be so Hard on Yourself," Glynne recently released her third studio album, "JESS."

Soul Symphony also will be returning, playing before Saturday's game. (6 p.m. BST / 1 p.m. EST).

Ceremonial first pitch

It's one of the greatest honors that can be bestowed on a fan or celebrity: The right to take the mound and toss out the ceremonial first pitch. Before Saturday's action, actor Matthew Broderick -- known for his iconic roles in "Ferris Bueller's Day Off," and "The Producers," -- will get the action going.

On Sunday, Phillies fanatic (not the Phillie Phanatic, though), "It's Always Sunny in Philadelphia" star and co-owner of the English Football League's Wrexham AFC, Rob McElhenney will be throwing out the first pitch. But who will he choose to have a catch with: Current star Bryce Harper or retired Phillies legend Chase Utley?

Mascot races

Not only will the Phanatic and Mr. Met be making the transatlantic trip, but your favorite giant headed mascots like Winston Churchill, King Henry VIII and Freddie Mercury will be on hand for the traditional mascot race. Who knows, maybe there's another fan favorite who may be making a return appearance this year ...

National Anthem singers

A Major League game can't begin before the anthem is sung. With the game taking place in England, both the U.S. and UK anthems will be sung. On Saturday, the NHS Choir will sing both anthems, and on Sunday, Broadway musical star Marisha Wallace will sing "The Star-Spangled Banner," while Welsh classical music artist Katherine Jenkins will perform "God Save the King."

Trafalgar Square

Even if you can't make it out to the ballpark this weekend, there is still plenty of baseball that awaits you. Head over to iconic Trafalgar Square to take in screenings of both games, complete with DJs and between-innings entertainment, along with New York and Philly-inspired food for sale.

In addition, you can work on your swing inside one of the 10 batting cages, while getting input and help from the baseball coaches that will be in attendance.

Don't miss Friday night, either: Before the Series kicks off, Utley will face off against former Mets second baseman Daniel Murphy inside The Cage for a unique augmented reality home run derby. Afterward, Phill Jupitus will host a special London Series Pub Quiz.